Top 10 garden problems & solutions

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:

1) Trees breaking walls or lifting paving

This Searsia lancea, planted too close to a boundary wall, has already had to be cut in half, and is lifting the paving

Arguably 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 walls

If 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.

2) Poor drainage & flooding

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:

Contouring & dry riverbeds

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 garden

Adding 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.

Drains & PVC pipes

A grid and PVC piping helps move rainwater away from this patio area

Whilst 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.

Replacing lawn with bedding plants

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.

3) Dead or sparse lawn in shady areas

Lawn in shaded areas of the garden - one of the most common garden problems

I 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 together

LM, 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.

4) Overwatering

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 leaves

One 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.

5) Alien invasives in the garden

An alien invasive Syringa (Melia azedarach) growing amongst the indigenous species on this verge

The 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 bird

Gauteng 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.

6) Rubble in the garden

Rubble lifted from just below the lawn of a small garden in Midrand

Rubble 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.

7) Faulty or inefficient irrigation system

Poor quality cabling can cause numerous problems in irrigation systems

As 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.

8) Garden pests and diseases

Pests such as the Amaryllis Lily Borer (left) and Aloe scale (right) can be major problems in Gauteng gardens

As 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.

9) Bare soil

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 home

Instead 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.

10) Dogs destroying the garden

Dogs can cause havoc in a small garden, digging up plants and damaging the lawn. Part intervention and part compromise is usually required

I 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!

Other garden problems we encounter

Below is a list of other problems we encounter, some of which might overlap with those listed above

Lack of a mowing edge

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 problem

One 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.

Inadequate lawn care

Apart from mowing, weeding and watering, lawns require seasonal maintenance to prevent them from falling into disrepair

Lawn, 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 difficult to reach places

Lawn in this area can be changed to an indigenous bed, which will reduce maintenance time and costs

We 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 headache

Some 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.

'Messy' plants

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.

Rock in the garden

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 garden

Having 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.

Poisonous plants

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

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.