Indigenous landscaping & garden design
in Johannesburg & Pretoria, South Africa
in Johannesburg & Pretoria, South Africa
Today we thought we'd briefly illustrate how a garden evolves over time.
When we design gardens, we plan their layout with a long-term goal in mind, usually 5-10 years. This means ensuring that the major structure of the garden is appropriate for when the garden has matured. It's important to note however that the changes that take place during that time may necessitate a change of some of the plant species, specifically the lower growing perennials and small shrubs. When designing a new garden, it's impractical to select shade-loving species - e.g. clivias - for a particular area when we know they are going to be in full sun to start with. Yes, that area may become shaded over time - because we have planted a young tree there - but that shade might only be 5-10 years away, so in the interim we'll choose sun-loving plants, or semi-shade plants, to fill those spaces. Over time, as the garden matures, those plants can then be swapped out, or transplanted to other areas of the garden that may better suit their requirements.
So, to illustrate how a garden can change over time, I thought it would be insightful to show you the evolution of a small townhouse garden, from inception to what it looks like now. Although these changes take place over many years, and there are a number of intermediate stages missing, these images should help you appreciate how a garden can change over time, and how yours can too if you design, implement, and manage its growth appropriately.
We've visited many gardens in Gauteng over the years and have had the opportunity to see a number of problems that homeowners face. In most cases the problems are not unique, and might have simple solutions, whilst in other cases - such as a tree breaking a boundary wall - there may be costly expenses involved to remove the problem tree and repair the wall.
In this article I want to cover some of the common problems we encounter and how they can be solved. Please keep in mind that we've had to use our discretion as to how to define the problems, because in some cases the problem might simply be a symptom of a larger issue. A fungus attacking your plants, for example, might be a symptom of a garden that is being over-watered, whilst a patchy lawn might indicate that you have rubble under the ground. To this end I've tried to be as logical as possible in my approach to the list, and as always would welcome your feedback on the items you feel might need further explanation, or other problems you think should be included.
Herewith are 10 common gardening problems we encounter, and their solutions:
This Searsia lancea, planted too close to a boundary wall, has already had to be cut in half, and is lifting the pavingArguably the most common problem we find in gardens is poor tree selection and placement, resulting in damaged boundary walls, the lifting of paving, or tree roots that interfere with house foundations. Unfortunately, it is all too tempting to place a young tree close to a boundary wall, either because the homeowner or estate wants screening right up against the boundary wall, or because the bed doesn't have enough space. From experience we know how difficult it can be for a homeowner to plant a tree even one meter away from a wall, often because they don't want to take up too much lawn space. Unfortunately though - depending on the species - some trees can eventually become problems, and can end up doing damage.
Trees such as this exotic Ceiba speciosa (Silk floss tree), whilst beautiful, can easily lift paving and crack boundary wallsIf you have a tree that is starting to affect a boundary wall, be proactive and remove it, or transplant it if it is still young. For new trees take into account the full-grown height and width of the tree and plant it accordingly. For small trees we recommend a distance of at least 1.5 - 3 meters from the boundary wall, whilst larger trees should be planted at least 4-7 meters away from walls and foundations. For further reading visit our "Trees breaking walls" and Top 10 trees articles.
One of the most common problems homeowners face - usually at the start of the rainy season - is that of poor drainage. Drainage problems usually only become evident when there is a heavy downpour, and a combination of factors can result in flooding in various parts of your home. Your neighbour's run-off water, for example - which by law you have to accept - can result in a torrent of water flooding through your property. Lawn also has a poor infiltration rate, and can easily flood, so a large lawn area -depending on its gradient - could direct water right up to your house. Even beds that have become rock hard due to inadequate use of groundcovers, or constant digging of the soil, can become problem areas. And we have had one instance where a client's home was flooding because the estate installed a speed hump on the main road, which inadvertently diverted run-off water into the client's garden and up to their house (see our African Birdlife article "Go with the flow").
Although flooding is a stressful event and can be damaging to a property, there are many actions you can take to resolve it. Below are some of the options:
A dry riverbed can be used to channel drainage water through the garden and out of the property. Adding rocks, pebbles, and water-loving plants helps to make it a feature of the gardenAdding contours or dry riverbeds to your garden is a great way to direct water away from the house. It is simple to do - albeit labour intensive - and involves understanding where the water is coming from (e.g. gutters, your driveway, your neighbour), where you want to direct it (your next neighbour, outlets to the street), and then raising or lowering the ground to direct it accordingly. A dry riverbed can also look beautiful even when it is not raining, by adding rocks, pebbles and gravel, and water loving plants to add to the aesthetic appeal. Contours and dry riverbeds are usually more efficient than drains at moving water, because they can handle a large volume, and because they do not get clogged as easily with debris - something that is almost always present with the first heavy rains. Additionally, a well-designed dry riverbed can help to slow the water down, making it easier for the water to infiltrate your soil, and reducing the volume that flows into your neighbour's property or onto the street.
A grid and PVC piping helps move rainwater away from this patio areaWhilst contouring might be the ideal way to move water through a garden, it is not always practical, as some gardens might be too small or too flat to allow for contouring. In these cases, drains are usually the preferred option, and can be added along the sides of the house, a patio, driveway, or in the middle of the lawn or garden beds where water collects. The drain then feeds into one or more PVC pipes - usually 110mm in size - which take water away from the home and out of the property. The drain should be covered by a grid, or by gravel and a geotextile material to prevent it from becoming clogged.
Drainage systems can be also be used against retaining walls where water might collect, to prevent damage to the wall. In these cases, a perforated pipe is added at the base of the wall, and the space behind the wall backfilled with gravel and covered by a geotextile material. This prevents the build-up of water against the wall as it filters down into the perforated pipe and is discharged elsewhere in the garden.
Removing lawn and adding groundcovers to your garden is another efficient way of reducing run-off and potential flooding in your home. Lawns in general are compacted spaces, and have low water infiltration rates. By changing your lawn to a garden bed, you can increase the infiltration rate of your soil, and thereby reduce water runoff. We often get feedback from client's whose lawn we have replaced with bedding plants, who tell us their drainage problems have disappeared. If you do opt for this option, remember that the goal is to avoid bare patches and cover your ground with as many bedding plants as possible.
Lawn in shaded areas of the garden - one of the most common garden problemsI have always tried to promote the idea of lawn-free gardens, gardens which increase the biodiversity of an area and lower your maintenance costs. But lawns have their place, and many people could not conceive of a garden without some lawn to walk on, lie on, for their pets to run around on, or to play sport on with their kids. Lawn, however, is likely to be your highest maintenance plant, and there are a number of lawn problems we frequently encounter. One of these is lawn that is struggling in the shade. Usually these lawns are Kikuyu, a sun-loving species which slowly dies off in shaded areas. To solve this problem homeowners sometimes resort to cutting back their trees to let more light in, but this is usually a temporary solution, and if not done correctly can harm the tree. A better alternative is to use LM or 'Berea' lawn in the spaces where Kikuyu is struggling. This is an indigenous species that is better suited to semi-shade areas, and once established knits well together with Kikuyu.
A once struggling Kikuyu lawn (foreground), has been replaced in the shade (background) with LM lawn. As can be seen from this photo the two species knit well togetherLM, however, only works in semi-shaded areas (rarely in dense shade), and does not take heavy traffic very well. Other ‘shade-lawn’ species may have limited lifespans, and homeowners who try them often end up having to repeat the seeding or planting process every year or two. If, after trying LM, you still find your lawn struggling, it's best then to let go of your lawn and rather extend your beds, using shade loving groundcovers. Some of our favourite gardens are those with no lawn at all, shaded hideaways where homeowners have been creative in providing access without the need for sun-loving lawns. Converting your lawn into an indigenous bed is rewarding and liberating, and allows you to include a greater diversity of plants in your garden.
Overwatering compromises your plants and your garden. Here a Buddleja saligna (False Olive) is being over watered by an irrigation system, resulting in yellowing of the leavesOne of the most damaging problems we see in gardens is overwatering. Unfortunately, some homeowners feel the need to put down so much water in their gardens - often because they have a borehole - that they end up compromising their plants and their gardens. We've even met homeowners who were watering their gardens twice a day, every day, which is a waste of water and damaging to most plants. You really can kill your garden with too much kindness!
Overwatering a garden results in a range of problems, including increased risk of fungus and disease, leaching of nutrients from the soil, spongy lawns, and shallow root systems of trees. Often, if a tree falls over during the rainy season, it’s because its root system was not deep enough, a symptom that it had been overwatered for many years by an irrigation system. Many tree species also go dormant in the winter months, and require much less water, or no water at all. Understanding the water requirements of the various plants in your garden is important, and will help you manage the amount of water you put down. More importantly though, changing your garden into a locally indigenous space will mean you will require much less water, as the plants will be adapted to your climate and conditions.
An alien invasive Syringa (Melia azedarach) growing amongst the indigenous species on this vergeThe definition of a weed is a plant that is growing where it is not wanted. This, of course, is a fairly broad and open-ended definition, and doesn't define which plants might be weeds and which are not. Some people might view a particular species as a weed, whilst others view that same species as part of the garden. A homeowner trying to maintain a healthy Kikuyu lawn, for example, might view Cynodon as a weed, whilst a homeowner trying to maintain a highveld grassland might view Kikuyu as the weed, and Cynodon as part of the locally indigenous flora.
For our purposes we are trying to enhance biodiversity, so to keep things simple let's focus on alien invasive species growing in your garden, as these are certainly unwanted plants, and this is one of the most common problems we see.
An exotic Celtis sinensis seedling has taken root in this indigenous garden - almost certainly dispersed by a birdGauteng unfortunately is full of alien invasives, and most of them spread easily, outcompeting native species and compromising our environment. Most propagate by fruit/seed, which is usually dispersed by birds or animals, wind or water, or sometimes unwittingly by garden maintenance teams as they move around. Identifying alien invasives when they are young is key, but many can be difficult to identify, especially for the untrained eye, so calling a professional or using one of the smartphone identification apps can be helpful.
Removing alien invasives when they are young will prevent them from producing fruit/seed of their own, or becoming so large that they smother surrounding indigenous vegetation. Removing young specimens will also save you money, as it can be costly to remove them later once they have grown. Additionally, some species - such as Bugweed - can be toxic or cause skin irritations, so catching them early can help you avoid health problems with such species.
Common species to look out for are Privets, exotic Celtis sp., Syringas, Jacarandas, Bugweed, Lantana, and Pompom weed. All of these are invasive and can compromise locally indigenous habitats, and although established trees such as Jacarandas need not be removed, homeowners should nevertheless be proactive in removing young specimens.
If you are unsure what alien invasives might be growing on your property, contact us for a consultation - preferably with your gardener present - and we can assist you in identifying and removing them.
Rubble lifted from just below the lawn of a small garden in MidrandRubble is a problem we frequently encounter in gardens, and is usually not apparent to homeowners until they dig up their soil in preparation for gardening. In small townhouse complexes rubble under the lawn is sometimes the result of building contractors taking shortcuts, by dumping it in the garden instead of removing it from the property. Lawn is then planted over the rubble, and once the contractor leaves no one is any the wiser. Unfortunately, rubble in the garden limits the growth space for your larger plants, resulting in plants struggling in a particular area or continually dying off. We’ve encountered homes where a homeowner tries to plant trees but finds that the young trees keep dying. Only when we dig below the ground do we find that the garden is full of rubble, and the trees were trying to root through this. Fortunately, there are building contractors who follow best practice in this regard - protecting the topsoil and removing rubble - and many estates now enforce rules regarding rubble and topsoil. If you think you have rubble under your lawn, and are wanting to change it into a garden bed, you’ll need to remove it before you can reap the benefits of a lush and healthy garden. For more info read our rubble in the garden article here.
Poor quality cabling can cause numerous problems in irrigation systemsAs indigenous landscapers we prefer to not install irrigation for our gardens, and rather rely on rainwater or manual watering of individual plants if required. But irrigation is useful in certain circumstances, such as newly installed gardens, for lush lawns or thirsty exotics such as roses or azaleas, or for food gardens with herbs and vegetables. And since a faulty or inefficient irrigation system is one of the most common problems we see, I think it's worth having on this list. Many homeowners have spent good money on installing and maintaining an irrigation system, not to mention the borehole to feed the system, so having an efficient system is important.
In most cases a faulty or inefficient irrigation system can be traced back to poor design or poor installation. Irrigation is a competitive and unregulated industry, meaning anyone with a basic knowledge of water and pipes can install it for you. Unfortunately, this sometimes results in poor quality installations, without proper planning or design, or using poor quality materials. Common problems with installations include shallowly trenched pipes - which is the most labour-intensive part of the installation, cheap cabling, and lack of head-to-head design, resulting in overwatering or underwatering of certain areas. Poor trenching in particular is a major cause of leaking pipes, and one can hardly blame a gardener for puncturing a pipe that hasn't been trenched properly. As a general rule - and unless there are extenuating circumstances such as rock or house foundations - pipes should be trenched 400mm below the surface, and pop-ups fitted by means of swing-joints or flexible pipe. For cabling a minimum of 1mm GP wire should be used, and cables placed in a protective conduit. Finally, all systems should employ head-to-head design principles to ensure even precipitation over an area, unless there is a narrow bed, in which case an alternative sprinkling design - such as strip nozzles - can be used. An irrigation system can be an efficient way of watering your garden, but it's important that it's installed correctly. For more information read our irrigation system problems and solutions article here.
Pests such as the Amaryllis Lily Borer (left) and Aloe scale (right) can be major problems in Gauteng gardensAs indigenous landscapers, we find very few pests and diseases attack our client's plants, and insects that do eat the plants usually form part of the natural life cycle of the plant. The garden Acraea butterfly (and its larvae) is a good example. Its host plant is the Kiggelaria africana (Wild Peach), which the butterfly lays its eggs on. When the eggs hatch an eruption of black caterpillars appears on the leaves, slowly eating away at the leaves until they can strip the tree bare. But this is a natural process for this tree, and it soon bounces back with a healthy, fresh set of leaves. The caterpillars in turn are food for cuckoos, which enhances the birdlife in your garden, and caterpillars that don’t get eaten soon pupate and turn into butterflies again. These are therefore not pests, but rather insects that form a natural part of the food chain and the life cycle of our indigenous plants.
But there are some insects we encounter which do not seem to have locally occurring natural predators, and for these insects intervention is sometimes required. The Amaryllis lily borer (Brithys crini) is an example. The moth of this species lays its eggs on some of our most prized plants, specifically clivias, crinums, and agapanthus, where the larvae then hatch and bore into the leaves. Left unchecked the larvae bore further down the leaf and into the bulb, where they damage the bulb and may kill the plant. A large infestation of this species is a serious problem in a garden, and can cause havoc on a group of clivias. Because the larvae do not appear to have any locally occurring predators - at least here in South Africa - they have become a major problem in gardens around the country. To resolve this many homeowners resort to pesticides, but a better alternative is manual intervention, where you take the place of a predator and manually remove the infected leaves and kill the larvae. This is a time-consuming (not to mention squeamish) process, but if homeowners and their gardeners are proactive it solves the problem and avoids you having to put down pesticides, which can compromise the wildlife you do want. Alternatively, there are some gardeners who leave the borer alone, preferring to let nature take its course, and they subsequently find that not all their plants get damaged or destroyed. If you are such a gardener please leave us a comment in the comments section below, so that both us and other gardeners can learn from your experiences.
Another regular problem we encounter is aloe scale, a white scale insect that has proliferated throughout Gauteng and turns the leaves of your aloes white. These insects are sap-suckers, and if left unattended will eventually kill the aloe. There are multiple interventions to them, including cleaning the scale off with a soapy liquid and soft brush, using a high-pressure hose, or spraying the leaves with an oil - either a cooking oil or an organic product available from your local nursery - which suffocates the insects, allowing the plant to eventually recover.
I'm sure a few homeowners are wondering why bare soil/ground might be a problem in their garden, afterall, there are plenty of gardens with bare soil! But bare soil is a problem for a number of reasons, and is not the norm in our naturally occurring grasslands, bushveld and forests. As Frits van Oudtshoorn points out in his wonderful book, "Veld Management, Principles and Practices": Mother nature does not like to be naked.
Think about this in terms of your own garden. If you dig up a garden bed, for example, but leave the soil bare, what happens? After a while the first few weeds start taking root, and within a few months to a year it is likely your bare soil will be covered with plants again, albeit with plants you may not want. This is one of the reasons some homeowners feel the need to constantly dig their soil, because otherwise it looks 'messy'. But digging the soil only perpetuates the problem of bare soil, resulting in degradation of the soil - damage to healthy microbes and fungi, a lower water infiltration rate - which results in soil erosion and drainage problems, and dust around the home.
Bare soil such as this has developed a hard crust, resulting in water run-off, drainage problems, soil erosion, and dust around the homeInstead of digging bare soil, cover your beds with low growing groundcovers, or pioneer grasses (if you're developing a grassland), which will cover the soil and help protect it. This is known as a 'living' mulch, or a crop cover in agriculture. In between your planting you can then use an organic mulch whilst you wait for your plants to grow (read our mulch article here). Covering your soil with plants will increase your soil's water infiltration rate, reducing soil erosion and drainage problems, and protecting your home from dust. Additionally, dead plant matter can be left in the beds to slowly decompose and enrich the soil.
Dogs can cause havoc in a small garden, digging up plants and damaging the lawn. Part intervention and part compromise is usually requiredI have left this problem for last, specifically because it is one of the most difficult to solve. Dogs are not only our pets, they're family, and allowing them to roam freely in the garden allows them to dissipate all of that excited energy they have within them. Unfortunately, especially in small shady gardens - dogs can cause havoc to lawns and our plants, either digging holes or pulling the plants out. Sometimes dogs will pull out plants that you have planted yourself (as opposed to plants planted by someone else), which might be a sign that they are competing with the plant for your attention! (Perhaps a dog expert can answer this?)
A small garden that has been dug up by your dogs can become a problem in the rainy season, especially if your dogs bring half of that soil into the house. We have managed to solve these problems somewhat by planting hardy, unpalatable plants, such as Dietes, or placing dump rock in the garden - which is usually not aesthetically pleasing. Spiny plants, or foul-smelling plants are not as successful, and dogs can get quite creative in getting around these. Other interventions - though more expensive - are electric pet cables, which issue sound alarms or small shocks to your dog, thereby teaching them to stay out of the beds. But these are restrictive measures, especially in a small garden, and at the end of the day the garden should be there for everyone, including your pets. If you have a solution to this problem please let us know in the comments section below, as I'm sure many dog owners would love some practical advice!
Below is a list of other problems we encounter, some of which might overlap with those listed above
Lack of a mowing edge (left) can make it difficult for your gardener to maintain the 'line' between your lawn and your beds. Adding a mowing edge, such as precast cobbles (right), solves this problemOne of the goals of a gardener or garden maintenance team is to keep your garden looking neat, and one of the ways to do this is to ensure that there is a neatly clipped line between your lawn and your beds. Unfortunately, this can be difficult for gardeners, as they often have to use a spade to keep the edge of the lawn straight, which results in the lawn slowly being chipped away at until your beds have increased in size. Lawn, by definition, is an artificially manipulated plant, and if you have not defined its boundaries then you might always struggle with this problem. Instead of blaming your gardener for increasing the size of your beds, make his or her life easier by edging the beds with an edging material. Some of the options here include rocks, wood, or a cobble edging - preferably cemented into place. There are also commercial products on the market (made from steel) which are specifically designed for this purpose. Using one of these solves this problem immediately, allowing everyone involved in the upkeep of your garden to know where the lawn ends and where the beds begin.
Apart from mowing, weeding and watering, lawns require seasonal maintenance to prevent them from falling into disrepairLawn, as we have mentioned, is likely to be your highest maintenance plant, and limiting it in your garden can save you maintenance and watering costs. But if you do have lawn in your garden, then it is important that you look after it seasonally to ensure it remains healthy. Kikuyu is the most common lawn used on the highveld, and we frequently encounter gardens where it has not been maintained or adequately cared for. Apart from regular mowing, watering and weeding, a healthy lawn requires additional maintenance which may include, scarification and hollow tining, top dressing, and fertilising.
Lawn in this area can be changed to an indigenous bed, which will reduce maintenance time and costsWe frequently encounter gardens where lawn, for one reason or another, is being kept in difficult to reach places. Sometimes this can be between a bed and the boundary wall, which requires the gardener to somehow get the lawnmower or weedeater into this area in order to maintain it.
Lawn behind this rose bed adds an unnecessary maintenance headacheSome homeowners leave the lawn because they cannot think of anything else to use, when in reality a garden bed with low-growing groundcovers would be more appropriate. Think about all the spaces where you have lawn in your garden, and consider whether a garden bed might be a better option.
One frequent complaint we receive from homeowners is that certain plants in their gardens are too 'messy', dropping too many leaves, fruit, or flowers onto their paving or into their pool. It's true that some plants are more problematic than others, and generally one needs to live with this problem or remove the plant. Often the plant in question is an evergreen tree, and some of our most beautiful evergreen trees drop a large number of leaves all year round. To keep things in context, it's not the tree's fault, but rather its selection and placement, so if it isn't doing any damage then the ideal scenario is to leave it and work the additional maintenance into your schedule. Otherwise, trimming the tree back can help, so long as it is done professionally to ensure the tree maintains its natural shape.
Gardens such as this are challenging and require some creativity. Indigenous grasses and hardy succulents can help turn a barren and rocky space into a beautiful gardenHaving a garden that contains natural rock can be a benefit to the homeowner, by providing a unique 'rocky outcrop' habitat that other homeowners try to artificially replicate. Additionally, there are many indigenous plant species that one can use in such a scenario, provided there is a bit of soil to work with. Unfortunately though, some of the gardens we see have so much rock that it leaves the homeowner perplexed as to what to do in order to create a beautiful garden. In these cases, one generally has to be creative in solving the problem, either by building artificial planting spaces, or decking over the area and making use of potted plants. Sometimes one might be able to jack-hammer part of the rock away, provided it is practical to do so and is not going to compromise a boundary wall or foundation. If you live on a rocky ridge you might be able to create a grassland or succulent garden, and often this can result in a unique and rewarding layout.
Once in a while we are consulted by homeowners who are concerned that they may have poisonous plants in their gardens, which are affecting their children or their pets. These cases are few and far between, but it can be a concern - especially if your little ones are constantly 'taste-testing' your garden. In most cases we find that the problem plant(s) are exotics, and some species are notoriously problematic. Many exotics, like Melia azedarach (Syringa) and Solanum mauritianum (Bugweed), have proliferated throughout Gauteng, and regularly pop up in gardens, often dispersed there by birds. If you are concerned that your pets or children may be negatively affected by plants in your garden, consult first with an expert to catalogue the species you have, and once you have this list you can then make an informed decision as to which plants may need to be removed.
Hail damage to your plants can be a painful experience to go through, especially if you have worked so hard to get your garden looking picture perfect. Unfortunately, there isn't much you can do about this problem, but the good news is that plants are resilient, and most will recover quickly from hail damage, sending out a fresh set of leaves. Our advice is to accept hail damage as part of nature, and remember not to throw away all those fallen leaves - as mentioned already they act as a perfect mulch to rejuvenate your garden.
Now that we're staying at home more often (after Covid-19) and finding new ways of living, many of us might find ourselves spending more time in the kitchen, preparing and cooking our food. This of course is a good thing, because it allows us to control exactly what we are putting into our bodies, allowing us to make healthier choices.
But if you are spending more time preparing and cooking food you might also find you have more food waste coming out of your kitchen. Peeling, cutting and chopping will leave you with a small heap of food scraps, which ordinarily might mean a heavier - and smellier - load of rubbish.
Food scraps/wasteAdding food waste to your ordinary bin load will likely mean it will end up in a landfill site, where it can rot and ultimately be detrimental to the environment. So rather than throwing your food scraps away, a better alternative is to bury it in your garden, where it can slowly break down into compost and enhance the quality of your soil.
Burying food waste is practiced around the world, and there are different methods, but the basic principle remains the same:
The food waste will then begin to slowly compost in your garden, helping to enhance your soil and creating a healthier garden.
But what if you don't want to dig a hole in your garden after every meal? In this case you can store your food waste in a Bokashi bin.
Bokashi composting is a Japanese system to help ferment food before it is buried in your garden, which has a number of benefits both for your garden and for the environment. Essentially it allows you to store food waste for an extended period without having any unwanted smells in your kitchen, and the process is simple to follow:
The composting process proceeds from there.
Bokashi bin with food waste
Bokashi bin food waste with a layer of Bokashi branWe add most of our food scraps to our Bokashi bin, including cooked leftovers and bones, and it significantly reduces our waste output, waste that would otherwise end up rotting at a landfill site. There are even some plants that we have buried our waste directly beneath before planting them, such as this young African Dog Rose (Xylotheca kraussiana).
(Thanks to Sanbi for the tip: "An excellent way to give this plant a good start in life is to plant it in a hole that has been used for your biodegradable kitchen waste." - http://pza.sanbi.org/xylotheca-kraussiana)
So next time you find yourself preparing food in your kitchen, consider burying your food waste in your garden, rather than throwing it away. Not only will you be enhancing the quality of your soil, you'll be helping the environment.
We recently completed the seasonal maintenance of a garden in Randburg, one which we installed over three years ago. The garden was relatively small - about 180 square metres - and consisted almost exclusively of indigenous trees, shrubs and groundcovers. Importantly, the garden did not have any lawn, a request our client had made during the initial design phase. The maintenance took us a day, with a team of six, and consisted of thinning out some of the overgrowth, pruning/shaping some of the trees and shrubs, and removal of a few exotic weeds which had taken root over the past year. In total the day’s maintenance cost just under R4000.
Whilst this might seem like a lot of money, it's important to note that this was the only maintenance that had been done on the garden in the past year. In twelve months there had not been a single gardener, or garden maintenance team on the property. The garden does not have irrigation, and had not been watered manually. The homeowner had simply relied on rainwater to water his garden, despite the fact that Johannesburg had recently experienced one of the worst drought periods in years, as well as extended heat waves. In fact, whilst many other gardens we saw were wilting and drying up - their lawns going brown - this particular garden had made it through the dry spell with no maintenance whatsoever, and still looked rather lush.
Think about this in terms of your own garden, and the expenses you might be incurring on a weekly, monthly, or annual basis. How does it compare? If you have a lush kikuyu lawn for example, how much does it cost you to maintain it? And if you have high maintenance plants such as hedges or 'lollipops', or exotic ornamentals, how much do they cost? To calculate some of these costs, here are some factors to consider:
All things considered, maintaining a lush green lawn and rows of hedges is usually a costly undertaking, and whilst these gardens might look beautiful for what they are, they are essentially high maintenance areas of your home, requiring time and effort to maintain. What's more, in terms of biodiversity, these gardens are relatively sterile.
Not long ago, I visited a show garden in the leafy suburb of Fourways. It was small and almost exclusively indigenous, and had very little lawn - perhaps only 5-10% of it. The garden was a wildlife haven, with numerous birds and butterflies visiting it, and I walked around enjoying the space and the sensory appeal of it. And then, by chance, I happened to look over the wall into the adjoining neighbour’s property. They had a typical suburban garden, with a huge expanse of lawn, and trees and shrubs set right up against the boundary walls. The contrast between the two gardens could not have been more striking, and I could not help thinking that for a small change of design, the neighbour could have had the same, sensory-appealing show garden as the one I was now standing in. Not only that, but they could have significantly reduced their maintenance costs.
Lawns, hedging and lollipops (left) take time and effort to maintain. Switching to a low maintenance, indigenous garden (right) can save homeowners thousands of rands each yearIf you're wanting to create a low maintenance garden in your home, here are some tips to get you started:
In many new housing developments, the developer supplies the home with lawn to give the homeowner something green to get him/her started. In many cases, the lawn may look green and healthy for a few seasons, but then gradually deteriorates, leaving unsightly bare patches. Often, no matter how much lawn dressing and fertiliser is applied, the lawn just doesn’t recover completely.
If there is limited traffic on the lawn, it is likely that the problem lies in the condition of the soil. To investigate further, you’ll need to dig to find out what is happening underneath your lawn. In the majority of cases, we find that the lawn was laid directly on builder’s rubble or over an area where the builders did their cement mixing. Here are 2 examples:
Example 1:
The lawn is patchy in this garden, despite efforts at seasonal top dressing and fertilising
Digging the lawn area to a depth of 20-30cm
During digging, bits of rubble become exposed, just below the surface of the lawn
Further digging exposes significant amounts of rubble beneath the lawn
Example 2:
A new lawn (dry kikuyu) is laid by the developer in this new complex garden prior to the home owner moving in
Removing the new lawn and digging below the ground reveals that the lawn was laid on top of a significant amount of building rubble
We removed the building rubble, prepared the soil with new topsoil and compost, and laid new lawn
A healthy lawn needs at least 20cm of composted topsoil so that it can send out strong roots to support the plant in times of stress (i.e. dry or extremely cold periods). In order to correct the underlying problems with your lawn, the best option is to remove the lawn, remove any rocks, rubble or debris, and prepare your soil to a depth of 20 - 30cm.
How to prepare your soil for lawn:
Once you have completed these tasks you can plant your lawn sods, or lawn plugs. If you are using sods, give the lawn one last roll with the roller once you have planted it, again to remove any air pockets and to settle it into your ground.
As indigenous landscapers we prefer to not install irrigation for our gardens, and rather rely on rainwater or manual watering of individual plants. But irrigation is useful in certain circumstances, such as newly installed gardens, for lush lawns or thirsty exotics, or for food gardens.
Unfortunately, there are a number of irrigation problems we frequently encounter, and in most cases, they can be traced back to poor design or poor installation, or inferior materials. In this article we'd like to discuss some of the most common problems and give some advice on how to fix them. Please keep in mind that every irrigation system is unique, and there may be valid reasons why a contractor has installed your system the way they have. Use this list as a guide, and as always, we'd welcome your questions and feedback.
Herewith are our top 10 irrigation problems and solutions:
Arguably the most common problem we encounter in irrigation installations is inadequate trenching of the pipes. Trenching is the most labour-intensive part of the installation, and is therefore sometimes neglected. Many installations are only trenched to the depth of the pop-ups (usually 20-30 centimetres), because this makes it easier - and cheaper - to join the pop-up to the pipe. Unfortunately, poor trenching can result in pipes frequently being punctured, either by yourself or your gardener. As a general rule – and unless there are extenuating circumstances such as rock or house foundations – pipes should be trenched to a minimum of 400mm below the surface, and pop-ups joined to the pipe via swing-joint risers or flexible pipe:
Not only does this keep the pipes well away from ordinary gardening tools (such as garden forks), but swing-joints allow you to easily adjust the height of the pop-ups in future if the height of the soil changes.
Perhaps the most common design flaw we see in installations is the lack of head-to-head design, which results in dry spots, overwatering, or underwatering of certain areas of the garden. It's a common misconception that if water from a sprinkler is 'reaching' a particular area, then that area is being watered. But the area covered by a single sprinkler is not watered evenly, because (as of writing) there isn't a sprinkler technology capable of this. In most cases sprinklers put down more water at the head of the sprinkler, resulting in an underground water profile that looks like this:
To create an even precipitation over an area, one needs a second sprinkler, placed at the outer radius of the first. Your underground water profile would then look like this:
This is known as head-to-head, and - provided each sprinkler has the same precipitation rate - creates an even precipitation over that area. Here are two scenarios from a top-down/design perspective for a rectangular section of lawn:
There are some exceptions. If you are watering a narrow strip garden, for example, then you can use strip nozzles instead. Capillary action through the soil in the narrow bed will then create a relatively even underground water profile. Likewise, if you are watering shrubs against a wall, you can use sprinklers that reach double the distance. Water droplets will then hit the foliage and trickle down, helping to even out the underground water profile.
Another common problem is incorrect pipe sizes - specifically pipes that are too narrow for the distance required. When water flows through a pipe a certain amount of pressure is lost due to friction (known as 'friction loss'). Factors affecting this include the diameter of the pipe, the length of the pipe, and the rate of flow (litres/min), amongst others. (Fittings, roughness of the pipe, and water temperature are also factors). Unfortunately, all too frequently, we see narrow pipes - usually 20mm LDPE pipe - used over too long a distance, resulting in a loss of pressure to the sprinklers. All sprinklers have a specific pressure rating at which they work most efficiently, and a loss of pressure degrades their performance and reduces their area of coverage. Additionally gear drives (rotors) require sufficient pressure in order to rotate, and may stop turning if the pressure in your system is too low. Calculating friction losses requires a friction chart or online calculator, but is an important step in the design of a system. If you currently have pressure related problems due to incorrect pipe sizes, you could try switching to nozzles that use less water (i.e have lower flow rates), or using a stronger pump (if you have a pumped system). Ideally though, pipes should be sized correctly to begin with, so removing old pipes and replacing them with new ones is the most appropriate solution.
Comms cables such as these on the right can cause electrical problems on your system and could void your manufacturer's warrantyAutomated irrigation systems make use of solenoid valves, which open and close to release water to your pipes and sprinklers. Power to the solenoid coils is supplied from the controller through cabling, with each station having its own cable and a shared common wire. Unfortunately, some systems are installed using inferior cabling, most frequently communications (comms) cables, which are not suitable for underground use.
Comms cables used on this system were left unprotected and exposed to moisture in the irrigation box. Apart from breaking easily, they shorted one of the solenoid coils, requiring replacement and repairThese cables can cause problems with irrigation systems, including shorting of coils or even shorting of a controller. In some cases, manufacturers may void the warranty if it is found that communication cables were used on a system where their controller has blown. For most systems, 1.0mm GP wire should be used for connections from the controller to the valves, and these cables should be placed in conduit (either 20mm or 25mm PVC or LDPE). Connections at the valves should also be waterproofed, preferably with silicone connectors. Finally, cables should be trenched appropriately, and - where possible - laid in the same trenches as the irrigation pipes, 400mm below ground.
The repaired box - a new coil and 1.omm GP wire in conduit, connected with silicone snaplocks
ABOVE: A Rainbird 12van nozzle with a precipitation rate of 40 mm/hr (square spacing)Understanding precipitation rates is one of the most important aspects to irrigation design, but is sometimes neglected, especially when maintenance on an existing system is conducted. Different sprinklers put down water at different precipitation rates, so mixing sprinklers with different precipitation rates can lead to overwatering or underwatering of certain areas of your garden. A 12-foot Rainbird cone nozzle, for example, has a precipitation rate of 40mm/hr (with square spacing). In contrast, a Hunter MP Rotator nozzle has a precipitation rate of 10mm/hr (with square spacing) - i.e. four times less water per hour. It's not difficult to understand then that if you have mixed these two nozzles on the same station, why one area of your garden is getting more water than the other. Additionally, the above two nozzles have different pressure ratings, so running them on the same station is inefficient use of one or the other. Similar problems occur when cone nozzles are mixed with rotors/gear-drives, as gear drives usually have lower precipitation rates. To avoid these problems, it's important to first understand the precipitation rates of each of your sprinklers, and to only use sprinklers with similarly matched precipitation rates and pressure ratings on the same zone.
The roots of an Acacia (=Vachellia) sieberiana (Paperbark) have crimped these irrigation pipesOne of the most common problems in established gardens is the crimping of pipes by tree roots. Sometimes this is due to pipes that have not been trenched correctly, but for the most part it is because the commonly used low-density (LDPE) pipe and fittings are too weak to handle the pressures of a large tree's root system. Sometimes - depending on where in the pipe this problem has occurred - crimped pipes can lead to burst pipes, because there is no longer any release of pressure via the sprinklers.
If you find that one half of your garden's sprinklers is working, but the other half is only trickling water, then this might be the problem. Troubleshooting it can be simple, provided you have access to the pipe on both sides of the tree.
Below is a test we conducted on two LDPE pipes that had been laid in the same trench:
At 2.2bar, the first pipe shows a flow rate of 44.9 litres per minute
At 2.2bar, the second pipe shows a flow rate of only 26.1 litres per minute - a 40% drop in flow rate. As this pipe was in the same trench as the one above, and there were no leaks or flow restrictions at the valves, the problem was traced back to crimping by tree rootsFortunately repairing a crimped pipe is relatively simple: dig down and find the affected pipe, then cut and replace it. If possible, avoid cutting the offending root and rather divert the new pipe around the root system - your irrigation is there to support the garden, not the other way round!
For new installations the use of hi-density (HDPE) pipe and fittings can mitigate these problems, so although these materials are more expensive, they provide a robust and long-lasting irrigation solution.
This Buddleja saligna (False Olive) - showing yellowing of the leaves - was being overwatered by an irrigation systemOverwatering leads to many problems in gardens, and is usually the result of poor irrigation design or incorrect timing/scheduling. We've met homeowners who were watering their gardens twice a day, every day, which was a waste of water and damaging to their plants. Plants that have been overwatered are susceptible to fungus and disease, whilst root systems of trees may remain shallow, thereby compromising their stability. To avoid overwatering your garden it's important to know the required amount of water for your plants per week, and to schedule your system accordingly.
Yellowing lawn is a possible sign of overwatering - here around the sprinkler headOn the highveld, the recommended amount of water for 'thirsty' gardens - that is gardens with large areas of lawn or species with high water requirements - is 25mm per week in summer. This 25mm should be spread evenly over the week, and only on alternate days (e.g. 8mm on Monday/Wednesday/Friday). Knowing your plant's water requirements and the precipitation rates of your sprinklers will help you calculate these figures. In winter, some plants go dormant, and may not require water at all. In these cases, irrigation systems should be set to reduce watering automatically - by using the seasonal adjust settings on the controller - or turned off altogether. Lastly, technologies such as rain sensors can pause irrigation when it is raining, and new controllers can connect to weather forecasts to pause the system if rain is expected.
Clogged filters should be removed and cleaned under running water. The pipe can then be flushed, and the nozzle and filter replacedOne of the most important maintenance tasks on an irrigation system is ensuring that the nozzles and filters are clear of dirt and debris. In some cases, especially after a pipe repair, nozzles and filters can become blocked with sand, something that usually occurs at the end of a line. If all the sprinklers in a zone are working fine, but the last one or two are only dribbling water, then the problem might be a clogged filter and dirt in the pipe. To resolve this, remove the head of the nozzle and clean the filter under running water, then run the system for a few seconds with the nozzle removed. This flushes out any remaining debris in the pipe, and the filter and nozzle can then be replaced.
Micro sprinklers are small emitters that are joined to your pipes via micro tubing. They are useful for difficult to reach places - such as potted plants - and are easy to install and use. In most cases they are attached to stakes, which makes them easy to move around. Unfortunately, they are frequently overused, often in places where other - more robust - sprinklers would be more appropriate. Micros require regular maintenance because the stakes are easily moved (often by dogs), and the tubing can easily be punctured by a gardener's fork. The heads may also pop off, or be accidentally removed, resulting in a wastage of water. Micros do have their place, but if you find they are a constant maintenance headache rather consider a more robust solution, such as pop-ups, risers, or drip irrigation, or consider manually watering your potted plants.
Dogs are our family, but they can be a real nuisance when they start chewing your sprinklers. The biggest problems tend to occur with risers, which are permanently above ground and therefore easy targets for an energetic dog. Short of taking your dogs for longer walks (to expel that pent-up energy), the easiest solution is to convert your risers to pop-ups, which would then be visible only when your system is running. (Set the system to run in the early morning or late evening when your pets are indoors or asleep). Alternatively, you could switch to galvanised risers and brass fittings, which are more expensive, but which will probably (hopefully!) solve your problem.
Read our article on garden problems and solutions here for more on dogs in the garden
One of the benefits of being a landscaper is that you get to see firsthand how seemingly benign planting practices from the past can cause major problems to an owner’s property.
One of the most common problems we encounter with regards to this is the planting of trees too close to a home, perimeter wall, or other hard structure such as a pool.
When planting a tree, it's important to choose the correct position in which to plant it as it can be a difficult and costly process to transplant or remove incorrectly placed trees. In most cases, incorrectly planted trees will eventually cause damage to property, so the first step to countering this problem is to research your chosen tree and take into account its full-grown size, growth habits and aggressiveness of its root system.
As an example, the picture below shows a tree aloe (Aloe barberae) planted next to a house to enhance the entrance. This is a magnificent sculptural plant that enhances modern architecture. It grows up to 18m tall and branches out to give a spread of between 4-8m.
In this instance however, it was planted too close to the house and its branches are already squashed in the limited area. The trunk of this tree also swells with age and can grow to a diameter of 3m, which would then interfere with the house. In this case the homeowners should remove the tree - as it is still fairly young - and transplant it to a safer area.
Sometimes though, gardeners aren’t responsible for choosing the position in which trees grow. In the picture below, an exotic Celtis (Celtis sinensis) has self-seeded itself in a sheltered position next to a house.
The seed may have fallen from a neighbouring property, or, more likely, the seed was deposited in the droppings of a bird. The problem is not so much that the tree reseeded itself, but rather that the young sapling was not removed in time - weeds often find their way into gardens via bird droppings. In this case the tree was left to grow, and has now grown to a height of 4m and could very possibly be affecting the building’s foundation. For situations like this, contact a professional tree-feller and have the tree removed. Also ensure that the stump and large roots are removed as it is likely to send out new shoots if left.
Several trees also have large surface roots that could damage structures or paving. In the picture below, the roots of a Silk Floss (Kapok) tree (Ceiba speciosa) on a verge have not only lifted the curb, but have also cracked the boundary wall.
Again, this tree should be removed by a professional tree-feller, the curb re-laid, the wall repaired, and a new tree (with a non-aggressive root-system) planted.
A final mention on removing and replacing trees: it is often a sad experience to remove a large tree from a property, but it is far better to save yourself the resultant costs of damage to property and to plant trees that will prove non-aggressive and just as effective in years to come.
These are some of the trees we commonly see growing around Gauteng that self-seed next to walls and wan cause problems if not removed:
So, to sum up:
For more information, read our Choosing a tree for your garden article, our Trees for small gardens article, or visit our plantbook.co.za website to browse and learn more about trees indigenous to Southern Africa.
Mulch is a layer of material that covers the surface of your soil. It can be a living mulch such as groundcovers, an organic mulch such as bark chips, or an inorganic mulch such as gravel or pebbles. It is often neglected in gardens, but plays a vital role in the health of your soil, helping to protect it from erosion, reduce weeds, increase water retention, and to feed nutrients back into the soil (living & organic mulches). Think of our forests; the layers of groundcovers, leaves, sticks and twigs that cover the soil, and you can begin to appreciate the benefits of replicating these aspects in your home. Even our naturally occurring grasslands and savanna (bushveld) regions have very little bare soil (provided they haven't been overgrazed), and instead are covered by low growing grasses and forbs (living mulch).
Here are three types of mulch, their pros and cons, and when to use them:
A living mulch, sometimes known as 'green' mulch or cover crop in agriculture, consists of groundcovers that cover the bare soil of your garden. These are usually low-growing species, either tufted or creeping, that work together to cover the soil and protect it, helping to reduce erosion, increase water retention, limit the growth of weeds, and increase biodiversity. In shaded gardens common species might include Chlorophytum comosum (hen 'n chickens), Plectranthus/coleus species, and Crassula species, whilst in a grassland species might include Eragrostis racemosa or E. nindensis, Sporobolus stapfianus and Microchloa caffra.
Groundcovers, such as Hen 'n chickens, can be used as a living mulchOrganic mulches are materials that are no longer living, but are still organic in nature. These could be dead leaves and twigs that are naturally found in your garden, or products such as bark chips or nut shells, available from your local nursery. Organic mulches can be applied to bare patches of your garden in a layer of about 5-10 centimetres, where they will slowly break down and help to enrich your soil. We use organic mulch in most newly installed gardens, but still prefer to think of it as a temporary solution until the living mulches - the groundcovers - spread and cover the soil.
Inorganic mulches are materials such as pebbles and gravel. They can be used effectively in small spaces such as atriums or in planter boxes, or in larger gardens where you want to create a succulent-themed garden. They come in a range of colours, so you can choose one that matches your garden theme.
