Top 10 trees to plant in a small garden

South Africa is home to a magnificent variety of indigenous trees and shrubs, and with a move by home owners towards the use of indigenous plants, it has become ever more important to choose species that will work in your home. Whilst many indigenous species are now being planted in gardens around Gauteng, not all of them are suitable for small gardens where walls, paving and house foundations need to be taken into account. Indeed, in my day to day consultations with clients I frequently come across gardens where incorrect species or incorrect planting techniques have been used, often leaving the home owner with costly expenses to fell problem trees or repair the damage to property (read about trees breaking walls here). Even seemingly innocuous exotics such as palms and yuccas can become problems over time, either putting pressure on walls as their stems bulge, or dropping heavy fronds and seed pods which can break roof tiles! Fortunately there are some beautiful indigenous alternatives that are ideal for small gardens, so to help you along we’ve created a list of the top 10 indigenous trees for small gardens on the highveld, with a selection below this list of species that would also be worthwhile. Please note that the list is entirely subjective, and we’d welcome your feedback on the selection. Here are the criteria used to compile the list:

  • The tree should be used more often as a tree, rather than as a shrub. i.e. we’ve excluded species that regularly feature as trees in tree books, but which we prefer to utilise as shrubs for our landscaping clients, e.g. Mackaya Bella, Freylinia tropica
  • The tree should not be too slow growing. Slow growing species are ideal for low maintenance gardens (read our article on a truly low maintenance garden here), but we generally find that our clients prefer trees that will reach a respectable height in a reasonable time. Note however that the terms ‘fast’ and ‘slow’ in the context of trees are relative terms! Indigenous highveld trees usually grow at a rate of between half a metre to a metre in a year – patience is always required when growing trees.
  • The tree should be moderately frost tolerant (although most trees should be protected from frost when they are young)
  • The tree should have a non-aggressive root system. This is usually a critical factor when planting in a small garden, although we still recommend that all trees be planted at least 1-2 metres away from walls, foundations and paving.
  • We specifically excluded trees that are usually planted for their structural appeal, such as Cussonia sp. and Aloe Barberae, the Tree Aloe (although both these species are also unsuitable for small gardens due to aggressive roots systems and bulging stems respectively.)

Please keep in mind that for very small gardens, e.g. 10 square metres or less, you may want to consider alternatives to the list below, or to grow your trees in pots. Use the list as a guide and base your decisions on the spread and height that each species will eventually provide, and what your ultimate goal for your garden is.

Herewith are our top 10 indigenous trees for small gardens on the South African highveld:

heteropyxis natalensis Lavender tree

With its pale bark, beautiful shape, and semi-deciduous foliage, the Lavender Tree, Heteropyxis natalensis, is one of our favourite small garden trees. It has a very ornamental shape, and is an ideal replacement for the exotic Silver Birch or ubiquitous Leopard Tree (Caesalpinnea ferrea). Lavender Trees are slower growing than other species on this list, but with patience they offer the home owner a beautiful specimen for their gardens. In the wild they are frequently found on rocky hillsides, and in Gauteng some beautiful specimens exist in the Tweedespruit conservancy on the outskirts of Cullinan.

This magnificent semi-deciduous tree can grow to over 12 metres in ideal conditions, but usually reaches between 8 – 10 metres. It has beautiful light grey-green foliage, and is ideal if you do not want your garden to appear too dark. The Kiggelaria has male and female parts on separate trees, so if you want a tree that provides fruit for birds you must choose a female tree from your nursery (Not an easy task for your nurseryman if the specimens are small! Try to look for the small grey-green fruit cases during the fruiting season, February-July) Female/fruiting trees attract a host of birds that feed on the orange-red seeds within the fruit casing, thus turning your garden into a natural wildlife haven.

kiggelaria_general

Both male and female plants attract the Acraea horta butterfly which lays its eggs on the underside of the leaves. When the eggs hatch an eruption of black caterpillars appear, which in turn attract insect eating birds, especially cuckoos (look out for Diederik Cuckoos). Some home owners become despondent when the caterpillars attack their plants, and some even resort to using pesticides to keep them at bay! But do not despair if you see caterpillars on this particular plant – this is a natural life-cycle for the tree and it will soon recover with a fresh set of leaves. The Kiggelaria is relatively fast growing, provides excellent screening, and has a sturdy trunk. All in all an excellent choice for the small garden.

The Buddleja saligna, False Olive, has become one of the most popular indigenous trees in Gauteng, and with good reason. At 1 – 1.5 metres growth per year it is one of the fastest growers on this list. The benefit to the home owner is that this species can reach a height of 3 – 4 metres in just a few years, thus providing excellent screening in the shortest possible time. However, being fast does have its disadvantages. Sometimes the Buddleja can look a bit ‘scruffy’ after a few years, and because the branches are not as strong as other species, they often tend to droop after heavy rains, especially if they are carrying masses of white flowers. Despite these potential drawbacks this is still a wonderful species to choose. Home owners should prune Buddlejas according to the shape they want them to grow – in other words, cut away lower branches to encourage a tree shape. You can even shape it into a hedge if you have the plants at a young age, and an excellent example of this type of pruning can be found in the Walter Sisulu Botanical Gardens:

If you allow it to grow into its natural form however you will be rewarded with masses of white flowers which attract a multitude of insects, and it’s not uncommon to see this plant covered in beetles, ants, butterflies and bees during the flowering season. Finally, do not confuse this species with its cousin the Wild Olive (Olea europeae subsp. africana). The latter is a much larger species and generally unsuitable for small gardens – see our section at the end of this article on why we omitted the Wild Olive.

The Pompon tree, Dais Cotinifolia, is one of the most beautiful indigenous trees and has become a very popular species in Johannesburg. It is an excellent substitute for the exotic Pride-of-India, and although it does not flower as long as that species, it’s explosion of pink flowers in summer provides a stunning display for any garden. The Pompon tree is a relatively fast grower and is frost tolerant. It is regularly used along pavements and sidewalks in Gauteng, and under certain conditions can grow to a height of 8+ metres. (although it will usually grow to between 6-8 metres). All in all this is an outstanding choice for your small garden.

The White pear, Apodytes dimidiata, is an excellent choice for the small garden. It grows at a medium pace, and its dark evergreen foliage makes it an outstanding screening tree. Like the Buddleja it can even be used as an effective hedge if pruned for this purpose, although I prefer to plant it to grow in its natural state. Apodytes will usually reach 6-8 metres, but may take about 8+ years to do so. It is an excellent replacement for the alien privet which unfortunately has proliferated throughout Gauteng. Look for the small black seeds with orange-red casing if you’re hiking in a kloof in Gauteng – a tell-tale sign that this species is growing close by.

This indigenous Pittosporum has become a popular garden subject, and has a large distribution on the Highveld. It is a medium-paced grower, is evergreen and makes an excellent screening tree. It sports beautiful yellow, edible berries at the end of the flowering season (April/May) which are well loved by birds. This species has a non-aggressive root system so it is safe to plant alongside paving or retaining walls. It also makes an excellent alternative to the exotic Pittosporum tenuifolium that is frequently used as a screening plant, so consider this tree if you’re in a complex or estate that requires the use of indigenous species.

The Wild Pear, Dombeya rotundifolia, is an indigenous species that can grow to a height of 8+ metres. This is a fully deciduous species, losing all its leaves in winter, so if it’s an evergreen tree you’re after then you’ll need to look elsewhere. Despite this it makes a stunning specimen for your garden in summer, exploding into masses of white flowers and making it one of the most attractive species on the list. If you find yourself hiking in one of the many nature reserves in Gauteng during the flowering season (July – October) keep a look out for this species as its flowers are striking and alert you to its presence. It has a non-aggressive root system so is suitable to plant closer to walls and paving.

This beautiful small tree or shrub is an ideal species if you have a very small garden space. It is semi-deciduous and sheds some of its leaves in winter, leaving behind small brown tube-shaped pods. It is very easy to grow from seed and you will often find small seedlings growing beneath adult plants in your garden. The flowers are a pink and white combination which attract a host of insects – so much so that we rate this as one of the most prolific insect attracting species. It is also a very fast grower, but this can sometimes be a drawback as the branches may be weak and break in a heavy thunderstorm. Despite these problems, if you decide to plant it in your garden you will soon find it becoming one of your favourite plants. Prune it appropriately in order to encourage a tree shape. A large specimen can be found growing at the entrance to the Walter Sisulu Botanical Gardens.

The Parsley tree is a common species of the South African highveld, and can regularly be found on walks and trails in Gauteng, particularly in wooded or rocky kloofs. It has dark brown bark that peels off of the trunk and branches, making it distinctive and relatively easy to identify in the field. It grows to a height of 8-10 metres and larger specimens will create a beautiful crown. This tree does have a tendency to spray its branches in all directions when young, but with patience it will turn into a magnificent specimen for your garden.

The Tree Wisteria, Bolusanthus speciosus, is a stunning small to medium sized tree that grows at a medium pace. It is an ideal replacement for the exotic Jacaranda, and although it does not grow as large as that species home owners should look at planting this species if they’re aiming for the same bluish-mauve colour in Spring. It has a non-aggressive root system and is a welcome addition to any garden. Beautiful specimens exist at the Pretoria Botanical Gardens.

Other options for small-medium sized gardens

In addition to the above list, here are a few more species for you to consider. Remember to base your decision on the full grown height and width of the species and how these dimensions will fit within your garden.

This beautiful evergreen to semi-deciduous tree is ideal for medium sized gardens. It generally grows straight and narrow and thus is perfect for narrow spaces in gardens and complexes, and is a popular choice for corporate office parks. It grows at a medium pace, with dark grey bark containing longitudinal fissures. These features along with its opposite and compound leaves make it relatively easy to identify and distinguish from other species. For those with patience it is a rewarding species and makes a beautifully shaped garden subject.

The ubiquitous Polygala myrtifolia is another very popular small garden tree, and if you have the space it is a wonderful species to have in your garden. It’s masses of purple flowers last for quite some time making it invaluable if you’re looking for indigenous colour in your home. The Polygala generally grows to form a large rounded shrub, which makes it a difficult species to fit into small or narrow spaces. The plant can also become quite ‘leggy’, and because it is a fast grower the branches may be weaker than other species – it’s not uncommon to see broken branches after a heavy highveld thunderstorm. Despite this it makes a wonderful garden subject, provides ample colour, and attracts a host of insects and birds.

Ilex mitis (Cape Holly)

The Cape Holly, Ilex mitis, is a magnificent, compact tree with an ornamental shape. Its dense dark green foliage combined with a pale and sturdy trunk make it diagnostic. In ideal conditions it can reach a height of 10+ metres. The Cape holly is a medium paced grower, and makes an excellent garden subject. It develops edible red berries and thus is very popular with birds during the fruiting season.

One of the most unique species on this list, specifically because of its distinctive growth of flowers on the stem. The small tube-like red or yellow flowers (depending on which variety you have chosen) attract nectar eating birds and insects, and these are followed by large green to black fruits which in turn attract fruit eating birds. On the highveld the Halleria generally grows as a very dense evergreen shrub, and is ideal to use as a screening hedge or simply as an insect and bird-attracting garden subject. Look for it when hiking in the wooded kloofs and gorges around Gauteng.

The Sand Olive is another beautiful small tree or shrub, and has become a popular plant in Gauteng gardens. It is evergreen, and develops clumps of diagnostic pale beige-green seed pods which make it relatively easy to identify in the field. Because of its dense foliage it makes an excellent screening plant, which in turn provides ample cover for insects and birds. It is a welcome addition to any indigenous garden.

This is a stunning ornamental species that carries edible red-berries which attract birds. A well-known specimen can be found in the Walter Sisulu Botanical Gardens where it has been propped up after having been struck by lightning a few years ago. Unfortunately the Olinia is very difficult to grow, and is difficult to find in local nurseries. It’s also a slow grower, so for these reasons we have excluded it from our main list. I should add however that if you’re not in a hurry, and are looking for a tree that is unique and will bring something special to your garden, then this is an excellent choice.

The Blue Guarri has a beautiful shape, and is abundant on the Highveld. It is a slow grower, so look to plant it with a long term goal in mind.

A beautiful ornamental shrub or small tree that reaches a height of about 3 metres. An excellent choice if you have a very small garden.

Vepris lanceolata (White Ironwood)

The White Ironwood, Vepris Lanceolata, is another excellent tree for the indigenous garden. It can be difficult to find in nurseries, but if you do manage to find one it is a worthwhile species to plant. It is evergreen, attracts birds with its fruit, and has a non-aggressive root system. It can be sensitive to frost, so keep this in mind and protect trees when they are young.

The Dogwood, Ramnus pirinoides, is a common species of the kloofs and gorges of Gauteng’s nature reserves. It is often found beneath the canopy of larger species, and is an excellent choice if you’re wanting to create a mini-forest of sorts in your garden. The small red-to-black berries are popular with birds making this a great addition to the bird garden. The glossy dark green leaves are also distinctive, making it relatively easy to identify in the field. The Dogwood will usually try to grow its sturdy branches in a horizontal ‘scraggly’ fashion, and hence we use it more for our clients as a large filler shrub rather than as a tree.

The Bladdernut, Diospyros whyteana, is another excellent choice for the small garden, especially if you’re trying to create a foresty feel. Use it in conjunction with the Dogwood (above) in order to create a forest-type environment. This species has uniquely shaped seed-pods which make it relatively easy to identify in the field if they are present.

A lovely small tree or shrub that is regularly found in the wooded kloofs and valleys around Gauteng. It has distinctively shaped bluish-purple star-shaped flowers.

A large, beautiful tree which resembles the smaller Lavender Tree is some respects. It is difficult to find in nurseries, and generally grows larger than would normally be suitable for a small garden.

 

Trees we specifically excluded from this list

The Cape Ash is a wonderful species that grows relatively fast and creates a dense crown. It has become a popular choice for sidewalks and shopping centres, and is ideal for spaces where you need to create a canopy in a relatively short space of time. It also has a non-aggressive root system, so is safer to use closer to walls or paving. We specifically excluded it from this list because it tends to grow very large and wide, over 12 metres high, and thus is generally unsuitable for small gardens where space is at a premium.

The Wild Plum is another very popular tree in Gauteng, being regularly used on sidewalks and in shopping centres. It tends to form a very wide, round and dense crown, and for this reason is generally unsuitable for small spaces.

The River Bushwillow is another tree that has become very popular in gardens and on sidewalks in Gauteng. This is a beautiful tree that grows to over 10 meters in the wild, mostly along streams and rivers – hence its name. Unfortunately it is generally unsuitable for small spaces due to the massive size and bulk it can attain, though this hasn’t stopped people from planting it in their small gardens! Keep a look out for its pale gnarled trunk on Johannesburg’s sidewalks, and then decide whether you have the space for it. If you can plant it at least three meters away from walls and foundations then you can use it. As a side note, it might be worth mentioning that its branches tend to break more frequently in heavy storms than other trees.

The Yellowwoods have become popular trees in Gauteng, and are especially common along pavements and sidewalks. In Johannesburg some beautiful specimens can be found on Katherine Drive just as you turn off from Marlboro drive towards Sandton. The Podocarpus is indigenous, evergreen, and is very sturdy. It is a slower grower than most other species, but if you have the patience it will be a worthwhile addition to your garden. We have excluded them from the above list because most of them eventually grow into very large trees, sometimes reaching a height of over 12 metres. The possible exception is the Podocarpus elongatus, Breede River Yellowwood, which generally grows to about 6 metres, but can also grow into a large tree under ideal conditions.

The Wild Olive has become one of the most widely used trees in Gauteng’s parks and gardens. It is a very common species throughout Southern African, and is very hardy and frost tolerant. Although it is regularly planted in small gardens, we would advise owners of small gardens not to do so, and to replace it whilst it is still small. This species will become a very large tree in time, and years from now you (or the next home owner) may find yourself having to remove it due to its size. As of this writing the cost of removal of a large tree can be as high as R3000-R4000 – and that excludes the fixing of the wall that the tree may have damaged. When it comes to the Wild Olive, there are many examples of large specimens in Gauteng, but my personal favourite can be found in Fourways on the corner of Douglas and Glenluce Drive. That specimen is in the company of a Searsia, and has taken many years to reach that size, but our goal as landscapers is to advise our clients appropriately, and so this species should really only be planted in medium-large gardens.

Vachellia/Senegalia sp. (formerly Acacia) are wonderful species to have in your garden, especially if you enjoy the bushveld and are wanting to recreate that particular habitat in your home. (Their names have changed recently – controversially – from Acacia). Most of these species have aggressive root systems, and some can grow into very large specimens. The beautiful Vachellia xanthophloea (Fever Tree) has become ubiquitous in Gauteng, and is regularly used in gardens, shopping centres, along sidewalks and in corporate office parks. Despite its frequent use and beautiful colouration, we would advise owners of small gardens to avoid the temptation to plant it and rather consider smaller species with less aggressive root systems. Take a closer look at the surface roots of a Fever Tree the next time you see one, and keep in mind that that is what it will try to do in your home!

It almost goes without saying that this large indigenous tree should not be planted in a small garden. Unfortunately the seeds of this species are regularly deposited by birds in and around homes, and unless the home owner is proactive in removing young plants they will soon become a problem. In fact this species, along with the exotic privet, are arguably the two most common trees we have to remove from our client’s gardens. If your home is big enough then by all means plant a Celtis – at least 3-5 metres away from paving or walls – but for smaller gardens, rather consider one of the options we’ve suggested above.

Feel free to comment on the above trees, and if you think we’ve missed one do let us know what it is and why you feel it merits a mention.

UPDATE: Thanks to Annie for your comment on the Combretum erythrophyllum (River Bushwillow), I’ve added it to the excluded list above