This blog lists shrubs, small trees, and other shrub-like plants that you can use as architectural form plants to create an eye-catching piece in your garden. When you add a couple of carefully chosen trees and shrubs and other shrub-like plants, you can go far in increasing the appeal of your garden. Furthermore, adding some of these plants to your garden will add interest and dimension. Turn dull uniform areas into modern, jaw-dropping show ‘pieces’. We have chosen some South African favourites, which we will discuss below.
Rhaphiolepis indica – Indian Hawthorn shrub
This is one of our favourite exotic shrubs or sometimes small trees. It is extremely tough, and there is little chance of something going wrong when you plant one of these shrubs. It will grow between 1.5 and 2m high, sometimes taller and about 1m wide. One can also purchase this plant in a lollipop form. Furthermore, it lends itself to pruning into a hedge and shaped plants.
Indian hawthorn has dark green leathery leaves and produces masses of white, light pink or dark pink flowers in profusion, creating quite a spectacular sight. These shrubs follow up their flowers with black berries, which are edible when cooked. Not only can you eat them cooked, but you can also make jam from them. The berries are also very popular with birds. Rhaphiolepis can be grown in sun / semi-shade and is drought-hardy. Moreover, it can tolerate heavy winds, including those of coastal/saline gardens, and grows in almost all soils.
Is it any wonder that we are in love with this spectacular plant? The only negative thing I can say about this plant is that they are slow growing, so you must be patient or purchase more mature plants.
one of SA’s favourite shrubs, The Hydrangea (Christmas Flowers)
We South Africans fondly call the Hydrangea ‘Christmas Flowers’. This is because these beautiful shrubs are always a riot of glorious blues and pinks during the Christmas season. Many people in the UK and the States know them as ‘Hortensia’. Brides often use them in bridal bouquets due to their beautiful pastel colours and prolific flowers.
Many people remember hydrangeas from their childhood. My mom’s garden had a row of gorgeous, large bushes that always flowered for months, and the flowers were always a part of the Christmas table arrangement. Sadly, her bushes have slowly diminished, mainly due to some severe droughts we had a few years back. These are thirsty shrubs; you must water them well in our baking hot summers to enable them to bloom and thrive.
Hydrangeas are great for shady garden areas but do better in light or dappled shade rather than full shade. They like well-composed soil and enjoy good feeding. Amazingly, you can alter their bloom colour to blue or pink by changing the soil’s acidity.
How do you change the bloom colour of your Hydrangea shrubs?
For blue hydrangeas, make the soil more acidic by adding acidic peat. Feed plants with 25g of aluminium sulphate dissolved in 5 litres of water at two-week intervals from early spring onward. For pink hydrangeas, make the soil more alkaline by adding agricultural lime. Dust lime at the plant’s roots and water them well at two-week intervals from early spring onward.
How do you stimulate your Hydrangea shrubs to produce more flowers?
Most of the Hydrangea shrubs available here are deciduous and flower better if you prune them back in Autumn after their flower season ends. However, this said, the delicate, dry flowers and skeletal petals are so magical that many folk leave them on the bush for as long as possible. Some even use dried flower heads in their floral arrangements to create a stunning effect.
Here’s a quick run-down of the two most popular varieties that we get in South Africa
MOPHEAD HYDRANGEA shrubs
‘Mopheads’, or Hydrangea macrophylla, are the most popular garden hydrangeas. Most ‘Mopheads’ that gardeners grow today are blue or pink, depending on their soil acidity. A few varieties are white.
The regular pink and blue varieties in the Western Cape are always available at the nurseries. Lately, we have a few lovely cultivars, like Hydrangea macrophylla ‘Maritzburg’ with dark pink flowers and white centres. Also, the ‘Endless Summer’ varieties, which promise to bloom all summer long, are available through our wholesale contacts. They come in shades of blue and pink and the white ‘Blushing Bride’. Macrophylla ‘Nikko Blue’ is an easy-to-grow mophead hydrangea which produces bright blue flowers in acidic soil. In alkaline soil, flowers are lilac to light pink.
LACECAP HYDRANGEA shrubs
Hydrangea macrophylla normalis or ‘Lacecaps’ have come onto the market more widely in South Africa in the last few years. You can grow them exactly the same as mopheads. We love them for their flatter flower heads and delicate petals frill. Hydrangea ‘Sweet Dreams’ is a lovely Lacecap available through one of our wholesale nurseries, Malanseuns, www.malanseuns.co.za. Macrophylla ‘Lady in Red’ is a white Lacecap hydrangea with flowers that mature to a deep red.
Duranta Erecta shrubs, also known as ‘Saphire showers’
The Duranta erecta is an exotic shrub that gets masses of sprays of dark blue flowers, which attract butterflies. This shrub is available in its natural bush form and standard plants to form more of a small tree. The plants and their flowers have a natural, lovely drooping look. This shrub is extremely hardy and also doesn’t require much maintenance. They flower better when planted in the sun.
POLYGALA MYRTIFOLIA SHRUB
The common name for this shrub, which has pretty mauve or purple flowers, is the September bush. The showy flower petals are beautifully marked with darker veins. Apart from the most common purple flowers, you will also be able to find this shrub with pink, scarlet, or white coloured flower petals. As the name suggests, this shrub starts blooming in early spring.
This evergreen shrub, which grows to a height of 0.6 to 1.8m, is also indigenous. You can grow it successfully in coastal regions as well as more inland. Therefore, it is suitable for various gardens and garden styles. Furthermore, it is a relatively low-maintenance plant that is also waterwise.
In a new garden, it is excellent as a fast-growing windbreak or hedge. Moreover, this colourful shrub can grow in most soil types, from full sun to semi-shade. Its growth is more lax, producing fewer flowers in the shade. However, it grows happily in the difficult pockets that change from full sun to semi-shade with the seasons. We love this shrub for its masses of pinky-purple sweetpea-like blooms carried in small clusters at the ends of short branches.
POLYGALA MYRTIFOLIA ‘WHITE FEATHERS’
Some new hybrids of the September bush shrub are now available on the market. One of them is the new white form called ‘White feathers’. The leaves of the white form are slightly greyer and contrast with the masses of small, white blooms covering the bush.
Polygala myrtifolia and its relatives, the smaller-growing Polygala fruticosa and the more upright version, Polygala virgata, are long-flowering shrubs that attract birds to your garden. Furthermore, these flowering shrubs also attract bees, butterflies, and chameleons to the fynbos garden. If you need to learn more about Fynbos garden designing, check out our blog.
Polygala myrtifolia works well at the back of a fynbos garden with other large shrubs like proteas (Proteaceae) and pincushions (Leucospermum), restios and evergreen shrubs. They can also be used as pioneer shrubs in a new garden because of their fast growth rate and ability to bloom when very young plants. The smaller, rounder form of Polygala fruticosa works very well as a shrub for the middle or front of the fynbos border, with its neat round mounds needing about 0.6m to exhibit their best shape.
Pruning your Polygala Myrtifolia shrubs
Polygala myrtifolia responds well to light pruning in Autumn or when the bush becomes a bit leggy. This encourages a bushy habit, but it is unnecessary on some plants or if you are happy to allow it to become tree-like. They can grow into a small tree up to about 4m if allowed to. Older plants can start to look untidy and woody, so heavier pruning is sometimes necessary to keep them bushy and flowery. Polygalas, in general, do well with a good layer of mulch covering their roots in summer to keep them cool. This helps to keep the moisture in and enables them to have low water needs once established.
Strappy and sword-shaped shrub-like leaf plants
Phormiums
Phormium tenax and other Phormiums. (The common name for Phormium tenax is New Zealand Flax) These strappy/sword-leaf, clump-forming plants come in various colours and sizes. Depending on the type and size, you can use it for mass planting, planting in small groups or specimen planting. Moreover, Phormiums make fantastic pot plants, combined with groundcovers planted around them to cascade out of the pot. These water-wise, low-maintenance plants prefer either full sun or semi-shade.
Cordylines
Cordyline australis (aka Cabbage tree or cabbage palm) and other Cordylines. These strappy-leafed shrub-like plants look similar to Phormiums but differ in that their leaves are a bit thinner and droopier. Instead of clump-forming plants, Cordylines grow on a cane stem. Varieties like Australis and Banksii are more sun-loving plants, whereas Cordyline terminalis is a broader leaf variety more appropriate for protected, shadier areas.
Sansevierias
The common name for Sansevieria trifasciata is the snake plant or mother-in-law’s tongue. Less well-known are the Sansevieria Hyancinthoides & pearsonii.
All Sanservierias are sword-shaped succulent plants. They, all being succulent, are extremely water-wise and pretty much hard to kill unless you manage to drown them. Moreover, they will grow indoors and indoors in sun, semi-shade or even very shady spots. Gardeners use these hardy plants in many different circumstances. Remember that they can be quite invasive sometimes, spreading via underground stems.
Yucca gigantea & other succulent shrubs
Yuccas are large growing succulent shrubs with sword-like grey/green leaves on top of thick cane-like stems. At some stage of their lives, they also get large heads of white flowers, which, believe it or not, are edible. This shrub is extremely architectural and eye-catching.
Dasylirion wheeleri shrub
This succulent shrub is a plant that grows on a short stump and has symmetrical rosette-packed spikey grey leaves with caramel brown split ends. This shrub is also very architectural. It looks great when combined with succulents and cacti, as it originally comes from Mexico. This shrub is very water-wise and likes full sun, so plant it in a sunny area.
Conifers
Juniperus scopulus ‘Skyrocket’. This conifer is pencil-shaped and looks similar to the ‘Stricta’. However, it has more of a blue-grey colour. Amazingly, it can reach a height of 6m but will only grow about 60cm wide.
Cupressus macrocarpa ‘Goldcrest’ This conifer, which grows wider, is eye-catching because of its bright green/ yellowish colour.
Cupressus sempervirens ‘Stricta’ is a pencil-like, thin, dark green-leaved conifer that is fantastic as an architectural plant. Although it grows very tall, it doesn’t grow wide. Gardeners love that it can grow in smaller places planted close to one another. These conifers remind me of Tuscan and Mediterranean gardens, where people often plant them in long rows next to one another.
Large leaf semi-woody Shrubs
Alocasia – These large-leaf tropical plants come in different types with different colour leaves. Some will grow outdoors in shaded areas, while others need to grow indoors. Although they don’t appreciate full sunlight, they are actually quite water-wise.
Philodedrons, various. These large-leaf shrubs come in many shapes and colours. They can grow both indoors and outdoors in shady or semi-shaded conditions. My favourites are Philodendron Xanadu, with fissured dark green glossy leaves, and Philodendron ‘Rojo Congo’, with maroon leaves.
Monstera deliciosa – This extremely large-leafed plant has glossy dark green leaves with holes, leading to its other common name, ‘Swiss cheese’ plant. It is a climbing plant naturally found growing up trees, so be careful as it can become invasive. The Monstera deliciosa can grow indoors and outdoors and makes a fantastic pot plant. It does best when one grows it in shady or semi-shaded areas. Plant in pots to control growth.
Strelitzia Reginae & other Strelitzia – These indigenous shrubs have spathe-like rough grey-green leaves and get bird-like blooms on stiff leaf stems. The Strelitzia Reginae gets orange and blue blooms, and the Mandela’s gold has yellow and blue flowers. Furthermore, you get the Strelitzia Juncea, off which the leaves never fully open. These water-wise plants do best and will flower best in sunny areas but can also be grown in half-sun areas.
Heliconia’s – Heliconia’s leaves are similar to those of the Strelitzia. They get extremely ornamental, brightly coloured waxy bracts. Depending on the type, these waxy bracts will be on upright stems, or some varieties will hang down. These plants belong in more tropical gardens and shouldn’t be planted in sunny positions.
Unusually shaped leaf tropical plants
Gunnera manicata—The Brazilian giant rhubarb is a plant with giant, deeply lobed leaves. This clump-forming perennial usually grows best along streams and in damp areas and likes well-composted soil. It grows about 2.5 m high and can reach almost 4m wide. It is more than often dormant in winter. This plant can be quite difficult to source.
Acanthus mollis – This clump-forming evergreen perennial has interesting, deeply cut, bright green shiny leaves and boasts spikes of creamy white flowers with purple bracts. These spikes actually make really good cut-flowers. This plant can either be planted in full sun or semi-shade.
Aloes, Cactis and other succulent plants used as architectural focus points.
Aloes
All Aloes are extremely striking in plant and leaf shape and their eye-catching flowers. This is a massive family, and all are so different. The tree Aloe or Aloe barberae is a striking architectural large growing succulent shrub. Furthermore, Aloe ferox and thraskii are also very architectural and stand out, making any garden more interesting. I recommend purchasing an Aloe book to determine what you would like and what’s appropriate for your garden if you like these plants.
Agave
Agave attenuate (Fox Tail Agave), Agave geminiflora (Twin Flower Agave), and others. These succulent-like hardy plants are extremely tough and don’t need much care. The Agave attenuata is a softer grey/green leaf plant that was very popular in landscaping. It wasn’t readily available for a while as it experienced a disease, but it is slowly becoming more available again. Be aware that some Agaves are invasive and shouldn’t be planted.
Furcraea foetida ‘Mediopicta’
This variegated succulent perennial forms a fountain of upright, long, sword-shaped leaves. The contrasting colours of bright green and creamy white are very eye-catching. Due to its shape and colouring, this plant is one of the most architectural. It is one of those plants that is difficult to kill and extremely water-efficient.
Euphorbia ingens, & tirucalli
Euphorbia ingens is an indigenous spiny, succulent medium to large tree. It can eventually reach a height of 6m. Although this tree is extremely form-like and attractive in its shape, please consider planting very carefully as the tree has a very poisonous latex, and the thorns can be quite dangerous. It needs very little care and is very water-wise.
Euphorbia tirucalli is a large succulent shrub or small tree with pencil/branch-like stems. When grown in full sunlight, these stems can display bright yellow, peach and pink colours. This plant does not have spines, but it does have poisonous latex.
Cyathea’s and other ferns
Cyathea (Alsophila) brownii & dregei – Tree ferns have an old-world feel and remind me of prehistoric times. The large fern leaves that spread out sit on an unusual trunk. Keep in mind that tree ferns and ferns, in general, prefer certain conditions. Grow in a shaded, protected position with little sunshine or wind in good-quality composted soil. Remember that tree ferns need space to grow as they grow quite wide.
Palms
Beaucornia recurvata – This unusual-looking plant is commonly named Ponytail palm because of its leaf structure. This evergreen perennial has an expanded or swollen caudex (or bottom stem) for storing water. The thin, strappy green leaves cascade, giving it that ponytail look. This plant can be grown indoors and outdoors, and it is a very water-wise plant.
Phoenix roebelenii – The pygmy date palm is a lovely small palm with a slender trunk topped with a dense crown of fine-textured, bright green fronds. This palm can be grown indoors and outdoors in full sun or part shade. This palm can either be single-stemmed or sometimes it will multi-stem. Moderate to low water requirements.
Reeds & Restios
Elegia tectorum (Cape thatching reed)– This plant has an upright, symmetrical, tufted reed-like appearance with thin, dark green stems. These are topped with brown flowers. This indigenous plant actually does like to be watered and can be grown next to water streams etc
Elegia capensis (Horsetail restio) – This indigenous plant has a drooping look, bamboo-like stems and feathery needle-like leaves. It belongs in wet areas along streams, next to ponds, etc, but can be grown in sandy soil as long as it gets enough water.
Cyperus papyrus (Paper reed) – This perennial sedge native to Africa forms tall stands of reed-like swamp vegetation in shallow water. It must either be grown in water or receive a lot of water.
In conclusion, this list includes only some of the most common shrubs and other popular plants used as architectural plants. There are so many more that one could discuss, such as bamboo, Cycas, Cycads, etc. Adding these architectural plants to your garden will definitely change its look and make it more interesting and modern. Be careful to research and choose the correct plant, as many of the above-mentioned shrubs and other architectural plants are not small plants and will occupy large spaces in your garden.
Article written by Jessica Ruger (Procurement at Contours Landscapes and Contours Design Studio and Horticulturist).
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