Our succulent rockery provides year-round colour, food for birds and insects, plus a water-wise, low-maintenance solution for a dry bank. Read further…
A steep north- facing slope in Gillitts, a small suburb inland of Durban, begs for a succulent rockery, the perfect design solution for an area that can otherwise be difficult to maintain. While lawn is particularly effective in preventing soil erosion on banks, slopes are difficult to mow and keep neat, but here, careful plant selection ensures it remains beautiful with minimal effort. As gravity pulls the rain water down the slope to the lowest point, water penetration is minimal and soils here, the upper sections especially, are usually dry; succulents do well in these conditions.
Senecio barbertonicus creates height at the top of the bank. A small to medium size shrub with a neatly rounded shape it has bright green needle-like leaves and acid-yellow flowers that attract insects and butterflies throughout summer. Tucking into the foliage of the Senecio is the tall
Aloe rupestris, the Kraalaalwyn, or Bottlebrush Aloe. The flowers are outstanding resembling short, cylindrical tubes, quite broad, either orange or yellow and all with dark red extended stamens that give this Aloe an attractive bicoloured effect. Flowering takes place in August and September when many winter flowering species have completed their show. Mature leaves are erect and spreading, and in cultivation, the Bottlebrush Aloe grows to just over 2 m in height.The red and green leaved Kalanchoe sexangularis tuck in around the stems of these larger species creating a neat border viewable from the bench nearby. It comes as quite a surprise in winter to see yellow flower heads forming on the maroon-green leaves, an unusual and striking colour combination. Alongside are 3 Aloe dyeri filling a small area of partial shade; this spotted ground Aloe has tall, slim columns of red flowers in early autumn.
The fat, spiny leaves of Aloe spicata will add additional height and strong form as they mature. Few nectar plants show the slow, progressive flower opening ritual as clearly as the 2 m single-stemmed Lebombo Aloe. An adaptation to ensure continued pollinator interest throughout the season, full bud formation is complete along the entire 50 cm long raceme, before a single flower opens. Wax-like buds are held horizontally, packed tightly around the core. Initially orange-red, they mature to a somewhat calmer orange-gold with a clear bright green longitudinal stripe – even the unopened bud is quite beautiful. Crassula capitella pools at its feet.
Bulbine abyssinica brings grass-like form and yellow flowers in spring; popular with bees, this Bulbine produces flowers off and on through the year. Favourites in this display are the spreading mounds of the lime green Crassula capitella; in autumn they grow straight up in narrow columns out of which pop creamy-white flowers that attract bees and butterflies from far and wide.
The dove grey/green of the Silver Lady, Kalanchoe thyrsiflora, borders this little cameo; in spring the flower stalks shoot up like a high-rise building, towering over its neighbours, a magnet for insects. This leaf mix ensures year round colour, even outside of their respective flowering seasons.
Soil stability on the slope comes from strategically placed rocks that prevent soil slippage and provide for small growing pockets that allow roots time to spread into the surrounding soil. Rocks are familiar and essential components of our South African landscape, and here they are used by reptiles to sun themselves or as a refuge to escape predators, as well as by butterflies to warm up on before they can fly. Birds will dig around rocks for insects they know lurk beneath them, and insect predators will lie in wait for a chance meal to crawl past! Rocks are probably most valued though through the winter months as they absorb the heat from a weaker winter sun and gradually releasing it into the night air.
This design focused on arranging combinations of leaf colour with flower colour more or less ignored– a mix of old favourites and new discoveries. It is always so exciting to receive a delivery of plants, offload them alongside each other, and in so doing, discover a new combination. The matching of Oscularia deltoides, Kalanchoe thyrsiflora, and Senecio crassulifolius was one such find. The greys and blues complement each other so well, touched off by soft silver and a dash of maroon, and the resultant mix is magnetic. In spring tiny pink and white daisy flowers cover the unusually shaped leaves of Oscularia, a little groundcover that hugs the ground and never gets out of hand. Relatively slow growing, it is easy to control in a confined space like a rockery. Here, the two colour palettes of the Silver Lady, Kalanchoe thyrsiflora, indicate how water and temperature fluctuations affect the leaf colour of many succulents. One group still wearing summer’s apple green we sourced from a coastal nursery; the other, sourced from inland of Pietermaritzburg, has already donned the red winter coat. The dwarf hybrid form of the Spekboom, Portulacaria afra ‘Nana,' a lovely dark-leaved succulent with a prostrate growth habit for stabilising banks, rehabilitates and restores soils, covers the ground between the taller species. As with its larger sibling, the dwarf Spekboom stores carbon.
Curio (Senecio) crassulifolius sits at the foot of the Kraalaalwyn, its plump blue fingers toning down the hot yellows and reds. Cotyledon barbeyi, or Plakkies, introduces beefy finger-like leaves of bright green and from March to September add flowers in a red to a coppery sheen that resemble hanging bells. Alongside is the superb Octopus Aloe, Aloe vanbalenii, whose tall stemmed flowers of yellow or orange brighten the garden from June to August. The amount of shade influences the leaf colour – red during times of drought and in bright sun, light green when slightly shaded or during the rainfall season. Deeply channelled leaves grow long thin tips that twist around and touch the ground. Thorncroftia succulenta will create a soft grey/green backdrop shrub behind the Aloe. Flowering from February to June, the purple tubular flowers will add a soft contrast to the hot colours that dominate. Crassula alba wearing its richly jewelled coat through April and May nestles in a rocky bed of its own the colours enhanced by another dove grey Oscularia spilling over a rock into the platform below. Aloe vanbalenii, hugged by the pale green leaves of Kalanchoe rotundifolia (previously K. decumbans, complete the last rock-pocket section. Flowers of this little groundcover are neon red-pink and form at the top of delicate stalks, well above the rounded leaves. A quite beautiful combination. Blond to green fronds of the odd NGongoni grass, Aristida junciformis, punctuate the display bringing in movement to the rather static forms of the succulents, and help to break up the strong form and colour of the succulents. That said, no other plant category adds the rich variety of colour with leaves alone. If you have even the smallest suitable space, treat yourself to a succulent paintbox!