A Winter Garden, Savanna-style
An impressive collection of aloes infuses this winter garden with colours of the sun
By Anno Torr
Along a quiet residential road in the hills above Durban is a sun-drenched savanna-style garden of thorn trees, aloes, and wild grasses, with bulbs and grassland forbs as summer-time treats. It is somewhat reminiscent of the Lowveld region around the Kruger National Park, considered by many to be the ‘real’ Africa. And it was planned as such 4 years ago, a way for the homeowner, Derek Rabie, to immerse the family in the landscape of his childhood. It is remarkable how well-established is this young garden.
On my first visit, the mid-afternoon sun streamed a slanting light that cast the scene in a warm, yellow glow, and I raced the growing shadows to get pictures before the sun’s early dip behind the neighbour’s boundary trees. It was a different light four days later, crisp and blue, and a warm, morning breeze rippled through the blond grasses. The aloes, though, posed like statues in still repose. Perfect!
No shadows to race this time around!
Many factors govern the distribution of the flora of our country: minimum temperatures, soil depth, aspect and slope, the water-retaining capacity of the soil, humidity, dry periods, and intensity and frequency of rainfalls. Therefore, for Derek’s vision to be successful, plant choice, as always, was critical, and here he had help from a retired nurseryman in choosing suitable trees that would give the savanna feel but thrive in local conditions. There are climatic similarities between the Lowveld and this Mistbelt suburb; mild winters, warm to hot - and humid – summers, and, of course, summer rains. Even pockets of frost and mist are common to both regions. And it is intriguing just how many of the notable Lowveld species grow down here too; amongst them are Schotia brachypetala, Cussonia spicata, Dombeya rotundifolia, Antidesma venosum, Jasminum multipartitum, Scadoxus puniceus, Carpobrotus edulis, Aloe arborescens, Aloe marlothii, Eucomis sp., Kniphofia sp., Bauhinia galpinii, and Leonotis leonurus, to name but a few.
Senegalia nigrescens (= Acacia nigrescens, Knob Thorn) is one of the characteristic thorn trees of the Lowveld; in the Durban/Pietermaritzburg region, other species reside; Vachellia karroo, Senegalia burkei, Senegalia caffra, Vachellia nilotica, and Vachellia sieberiana. The famous Fever Tree, Vachellia zanthophloea, is another thorn tree inhabiting the Lowveld, but, depending on microclimates, can struggle in the Kloof, Hillcrest suburbs. In this garden, they appear quite at home amongst their succulent and grassy companions.
Building the garden:
Day-long sunlight is critical for the plants that will make up this landscape, but exotic trees along the fence lines shaded much of the garden; removing them opened the space to the hot sun. Large blocks of lawn made way for deep planting areas and replanted elsewhere to consolidate the lawn area into a single space off the veranda. Seeded fodder grass provided rapid covered for the now exposed soil between the new plants, retaining moisture and helping to prevent soil compaction and erosion. Next in, a simple irrigation system to provide the water needed during the establishment phase; the water wise plantings are now self-sufficient in this regard.
Thorn trees line the driveway, positioned between Krantz Aloe shrubs in various colour forms – peach, yellow and shades of orange - with gleaming trunks of Vachellia zanthophloea standing sentinel at the far end. The Sour Fig, Carpobrotus edulis, provides a neat border along the length of the driveway and outer perimeter of the entrance garden. “It is the wrong plant for this area”, Derek admits, as it requires a lot of maintenance to keep it neat and to tame the wandering stems. Too narrow a space for this boisterous plant, I’d suggest. Less rambunctious is the small succulent groundcover, Crassula multicava, used to edge the inside perimeter but allowed to spread out and mingle with others, and find a way around and through layers of wild grasses.
An elegant wooden walkway leads to the main door and dissects both the space and design of this entrance garden.
The large grey leaves and cream flowers of Helichrysum populifolium tuck into the shadow of the house wall, a good choice to anchor the water feature here, while the Wild Dagga, Leonotis leonurus, squeezes into the narrow space against the wall.
Kniphofia and Juncus species are popular water feature plants, yet, as seen throughout the garden, they thrive in ordinary garden soils.
Lavender trees, Heteropyxis natalensis, give a dappled, woodland feel - new russet growth in autumn, glossy green mop-heads in summer, and a bare canopy in winter.
To the right, rocks and dead wood are strewn across the stony ground along with 2 replica dolerite outcrops so common through much of the Lowveld. A rusty warthog lurks amongst the grasses. And Derek’s aloe passion is immediately visible with Aloe gerstneri, Aloe castanea, Aloe tenuior x arborescens, Aloe chabaudii, A. cooperi, Aloe fosteri, and A. marlothii on show here. All planted as small specimens most are already well-grown with A. ferox already close to 1. 7 m. And a young Tilt-head Aloe, Aloe speciosa, already leans towards the sun. Kniphofia, Bulbine latifolia and Senecio barbertonicus add lime-green, lemon yellow and orange-red to this wintery scene.
Flowerbeds run along the periphery of the lawn and stretch the full width of the roadside wall; these are deep enough to provide sufficient planting space on either side of the cement path that snakes through its centre. All walkways, including the wood-slat entrance path, are built for wheelchair access and secure, easy movement, enabling all to enjoy the beauty of the plants. And in this hot, bright spot, aloes take centre stage. Derek’s Aloe collection is impressive, over 70 species, mostly South African, with the odd one like Aloe cameroni from across the border. The flowering time for many of them seems later than in past years; those in the know on plant forums Derek visits suggest the late rains have a part to play in this. Most of the A. vanbalenii buds remain tightly closed, for example, and this time last year the sizeable group of ground-hugging A. parvibracteata, were in spectacular flower; this year, only a few buds have formed. They were in need of rescue from beneath a layer of Aristida grass, though, so dense it blocked out the sun and air, and no doubt slowed down flower formation. Slightly blackened, they’ve recovered well enough to send up sturdy flower stems, and will hopefully open in time for the Kloof Conservancy Open Gardens this weekend (16 – 17 June 2018).
Still to open are the tight buds of Aloe cryptopoda (Aloe wickensii is now included in this genus; see further info in the image caption). Flowering time is as variable as colour form (red, yellow or bicoloured), with the main season from June to July, May in some localities, as early February or March in others.
Aloe maculata (Soap Aloe), and A. ferox (Bitter Aloe) provide the most striking display with the flat-topped pale orange flowers of
A. maculata at knee-height in front of the architectural shapes of A. ferox whose long, slender red flowers reach head height. Even the leaves of the Soap Aloe add to the colour spectrum tinged russet and orange in the dry winter soils. Front of bed the neat, upward-reaching grey leaves of the grey-leaved Aloe peglerae and young book-shaped A. suprafoliata line up along the gravel floor.
Adding some uncertainty to the mix are the tangling limbs of the rambling aloes, Aloiampelos tenuior, A. ciliaris and A. striatula, the distinctive shiny dark green recurved leaves of the latter forming a half-moon around a small pond. A. tenuior and A. ciliaris tuck in amongst the grasses using them as support.
My all-time favourite, though, is the Mountain Aloe, A. marlothii, with its yellow-and orange-gold tubes borne on horizontal or slanted racemes of which a mature plant can carry an impressive 20 – 30! The exerted (extending beyond the petal edge) stamens add an entrancing texture and provide easy access to pollen and nectar for the bees, butterflies, birds, and insects. Species both with and without spines on the outer leaves are present here.
A few tree aloes, Aloidendron barberae (= Aloe barberae) are scattered through the garden, drawing the eye with their distinctive sturdy trunks and leaf form, each one grown from truncheons rescued off the back of a municipal truck.
Worthy of mention is Aloe reitzii, a spectacular stemless aloe from the Limpopo, Mpumalanga area. It grows on granite outcrops and rocky slopes in grassland and savanna landscapes. SANBI’s Red List of South African Plants lists both varieties as Near Threatened to Critically Endangered with populations in decline. Other notable aloes include A. bowiea and A. pretoriensis.
As the spring rains arrive and the grass clumps are pruned to ground level the spectacular winter aloes give way to a parade of bulbs and grassland forbs, the composition continually changing as the display continues through summer. To date, Aristida junciformis is the single grass species used and it has seeded too generously through the beds, and dense end-of-season foliage has smothered a few small plants. Looking at photos of the new garden, I picked out a small clump of Berkheya speciosa in flower, but Derek and Sharon could not recall seeing them since that first year. “Aristida has no nutritional value”, Derek agrees. He plans to thin out the clumps and add local grasses like Melinis nerviglumis, M. repens, and perhaps even Rooigras, Themeda triandra.
In savanna bushveld landscapes, light, open tree canopies allow enough bright light to reach ground level for healthy growth and flowering of aloes, grasses and other shrubs. Here, Erythrina lysistemon and the slender Indigofera jucunda build the sparse woodland/shrubland structure underplanted with a spiky hedge of Aloe arborescens. A scattering of thorn trees through the grasses form small groups with aloes, grasses, perennials like Kniphofia and Bulbine latifolia; the shrub selection includes Coddia rudis, Crassula ovata, and Senecio barbertonicus.
Further along, a single Schotia brachypetala (Weeping Boer-bean) and 2 Grewia occidentalis (Crossberry) will in time add shade, along with flowers and fruits for birds and insects. A cluster of Buddleja salviifolia, cussonias (Cabbage trees) and Heteropyxis natalensis provide woodland and shrubbery structure in the corridor between the front and back gardens with an understorey of Halleria lucida, Plumbago auriculata, Leonotis leonurus, Helichrysum populifolium, and Aloe arborescens. Derek has plans to remove most of the Dietes grandiflora, but for now, they protect the soil and fill up space.
Water features of various sizes offer habitat to amphibians - toads, clicking stream frogs, painted reed frogs, and tree frogs – as well as dragonflies and other aquatic life. The most impressive feature is in the back garden where a series of ponds and waterfalls takes up much of the sloping space. Set a mere 2 m from the main bedroom, its toad inhabitants’ challenge the family’s sleeping patterns! Tilapia and a few turtles rescued from the pot live here in apparent harmony, but infighting amongst the turtles over the single female in the group resulted in a few high vet bills, and the males now reside in separate upper and lower-tier apartments. Cyperus, Juncus, Elegia tectorum, Plumbago, Tabernaemontana ventricosa, aloes, grasses, thorn trees, and Dietes provide dense, lush habitat around the pond edge. As this garden thrives for the most part on rainfall alone, rainwater collected in the large tank keeps this pond topped up.
The amount of ground given over to productive plants that fill both wildlife and human larders is impressive and nothing goes to waste. Leaves, grass clippings, and plant pruning’s fill an extra-large compost box measuring 3 m wide x 5 m long. Twice a year the gardener adds horse manure to the mix; once broken down, it acts as nutritious mulch on established beds, and as a layer in which to establish new beds or planting holes.
To date, Aristida junciformis is the single grass species used and it has seeded too generously through the beds, smothering a few small aloes and groundcovers. Looking at photos of the new garden, I picked out a small clump of Berkheya speciosa in flower, but Derek and Sharon could not recall seeing them since that first year. “Aristida has no nutritional value”, Derek agrees. He plans to thin out the clumps and add local grasses like Melinis nerviglumis, M. repens, and perhaps even Rooigras, Themeda triandra. This feeding regime appears to work well given the speed of establishment of this garden.
Derrick and Sharon have invited us back to see the spring and summer bulbs, and we will share this generosity with all of our readers in the coming months.