Very few gardens are static, they all go through an evolutionary process, starting off as sunny, ornamental trees and shrubs are planted for shade, windbreaks etc. and gardens develop - they start sunny and soon parts become shady, demanding an increase in the use of shade adapted plants.
Trees and shrubs are the first plants established in a new garden. The sunny garden is often gradually turned into a shady garden which poses new problems to the gardener (there is also the positive side, less frost damage under trees and near buildings!). As the trees and shrubbery increase their canopy, grasses and many sun-loving plants are deprived of light and sufficient moisture and nutrients. The result, dry shady earth. This is also especially true for the winter rainfall region in the Western Cape. The surface roots of the trees and shrubs also provide severe competition for other ground-layer plants. Buildings also ensure lots of shady microhabitats, such as the south side of a building remaining cooler and retain moisture for longer periods.
Fortunately for each shady situation, there is a suitable indigenous solution, even for fences, focal points etc. South Africa harbours one of the worlds richest floras, with several botanical hotspots; and many of our shade plants are international hits. Hen & Chickens or spider plants (Chlorophytum comosum) are one of the examples, regarded as the second most commonly grown shade plant. Clivia are increasingly used, and others such as Plectranthus gaining popularity. Sansevieria surviving on so many shady stoops, one of the hardiest, can tolerate neglect and abuse to the extreme! The number one survivor of total neglect!
"Fortunately for each shady situation, there is a suitable indigenous solution..."
What makes our shade-loving plants so special? Most have drought-adapted features, thus, tolerant of dry shady conditions. These features include shallow subterranean fleshy roots or water storage parts such as bulbs as well as above-ground fleshy parts. The latter include leathery to fleshy leaves. Most of these plant originate from dry forested river valleys in southern and eastern parts of South Africa (the southern & eastern Cape as well as KwaZulu-Natal a shade-tolerant botanical hotspot). Well adapted to forest disturbances, prolonged droughts, rainfall at any time of the year, and tree root competition, the main reason for their success in gardens thus where similar conditions reigns. There is therefore a suitable indigenous shady solution for all the major horticultural categories, even trees. These include shrubs, accent plants, climbers, ground covers etc.; thus even for shady fences, there is a suitable plant.
Establishment is vital, especially in a new area to be planted up. Subsurface competition is for water, nutrients and space, an intense battle for survival. Tree and shrub roots are the main culprits. However, once the shade plants are established, they would be able to cope better with dry conditions. The first year it thus crucial to provide a solid foothold. The soil should be well cultivated and tree roots removed and soil conditioned with compost.
Soil is the basis and the most important part of a garden. Most shade-adapted plants grow in slightly acid soils but some will tolerate soils with a higher pH. The upper layer of the natural forest is rich in leaf debris. This acts as a constant, slow-release fertilizer. The shade plants are naturally fed by falling leaves. That is why it is so important to keep this leaf litter layer. In the garden, this can be supplemented by adding compost, leaf mould or chipped bark.
Ground-living organisms continuously break down leaves and turn it into humus which plants can utilize. However, they need efficient moisture. Traditionally leaves and branches were carted away and our gardens impoverished. Thus important leaf mould organics or compost feeds, retains moisture and is essential for ground-living organisms. Additional feeding with natural products such as bounce-back can be added which would vastly improve plant health and condition. Old tree stumps act as slow-release, although taking years to decay they contribute to the health of the shade garden. Ample bone meal will also be beneficial.
After planting, thus make use of a mulch, and initially water frequently.
The best time of establishment is in spring, the start of the growing season of most of the shade plants. In winter rainfall regions autumn is also a good choice for establishment due to the start of the winter rainfall.
Embankments due to their sloping gradient rapidly lead to soil erosion and best planted with shade-tolerant plants which are good soil binders. It includes plants such as Hen-and-chickens (Chlorophytum comosum), Forest onion (Ledebouria petiolata), Plectranthus species etc. Embankments can also be terraced with dry stone walls or making use of tree trunks. Accent plants such as Dracaena aletriformis, Encephalartos villosus should also contribute to the scenery. All which would help to combat soil erosion.
Hen-and-chickens | Chlorophytum comosum
Plant categories for dry shade
There are many shade-adapted shrubs suitable for the various regions in South Africa. They can be established in shady parts (shade of trees, south side of buildings etc). These range from small and shrubby to almost tree size and their shapes vary from spreading to erect. Their leaves also vary in size and texture. The pioneer fast-growing species are great for a rapid result. The larger, such as the pistol bush (Duvernoia adhatodoides) and the Cape stock-rose (Sparrmannia africana) in the background blocking out views. Plectranthus ecklonii in its three colour forms ('Erma', 'Medley Wood', 'Tommy'), Plectranthus fruticosus ‘James’ and Plectranthus zuluensis are two fast-growing species when well established, being able to tolerate dry conditions.
Spurflower | Plectranthus ecklonii
Larger long-lived shrubs include the bird berry (Psychotria capensis), the yellow flowering Mickey Mouse bush (Ochna serrulata), Ochna natalitia), red flowering Natal flame bush (Alberta magna), pink flowering pink Carissa (Carissa edulis), white flowering small-flowered Rothmannia (Rothmannia globosa), bladder-nut (Diospyros whyteana), lemon thorn (Cassinopsis ilicifolia), orange flowering wild-pomegranate (Burchellia bubalina). Others include smaller long-lived shrubs such and the forest bells (Mitriostigma axillare), forest num-num (Carissa wyliei). The ribbon bush (Hypoestes aristata) etc. can be used on the south side of shrubby borders or in mass. The bird-berry a rounded shrub bearing leathery leaves, masses of yellow flowers popular among butterflies and followed by red (turning black) berries relished by birds. The latter a must of shady gardens.
Ribbon bush | Hypoestes aristata
Winter rainfall regions especially also provide a problem as during the dry summers the soil becomes very dry, demanding plants which can tolerate dry shady conditions. Plants with additional drought-tolerant features should be acquired. Apart from using suitable Plectranthus other useful candidates include the ground covers such as the forest crassula (Crassula multicava), Crassula spathulata, Crassula sarmentosa, Clivia miniata, wild asparagus (Asparagus densiflorus), forest sedge (Cyperus albo-striatus) and Veltheimia capensis. Accent plants such as Dracaena aletriformis, wild iris species (Dietes grandiflora and others), wild banana (Strelitzia nicolai, crane-flower (Strelitzia reginae) and forest cycads (Encephalartos villosus). The seven-weeks fern (Rumohra adiantiformis) will also tolerate dry conditions.
Forest lily | Veltheimia
Feature plants lighten up dull corners and add to the beauty of the garden. Their bold shapes or strong features eye-catching and can be used to create a special effect such as a tropical atmosphere. It includes the large-leaved Strelitzia species (Strelitzia nicolai, Strelitzia alba and Strelitzia caudata). The large- (Dracaena aletriformis) and small-leaved dragon trees (Dracaena reflexa) are also effective and the indigenous palms also tolerant of shade (Jubaeopsis cafra and Phoenix reclinata).
Crane flower | Strelitzia
Many cycads can be used in shade (excluding the grey of blue leaved species). The most appropriate, Encephalartos villosus, Encephalartos natalensis and Encephalartos paucidentatus. The smaller fern-cycad (Stangeria eriopus), fern-like and tolerant of dry shade. The tree aloe (Aloidendron barberae) are also shade-tolerant, however, can become very large. The smaller Tonga tree-aloe (Aloidendron tongaense, a smaller variation of the former a better choice for smaller gardens. The wild-iris (Dietes grandiflora, Dietes bicolor) also very appropriate smaller feature plants tolerant of dry shade.
Natal cycad | Encephalartos natalensis
The branched arborescent bushveld dragon tree (Dracaena transvaalensis) ideal for dry bushveld gardens.
Ground covers are plants which cover ground in mass with good soil binding properties. They are planted for a function, a green carpet below the trees. This group is very diverse, ranging from the forest sedge (Cyperus albostriatus), increasing by stolons to the Hen-and-chickens (Chlorophytum comosum) and bosplakkie (Crassula multicava). The latter three excellent ground covers, especially embankments.
Fairy crassula | Crassula multicava
Clivia (Clivia miniata) are also most useful, but slower to multiply, however a long term most appropriate soil binder. The forest onion (Ledebouria maculata) is a cluster forming bulb bearing spotted leaves in a rosette. The last two all great and tolerant of dry shade and easily propagated by division. The others from stolons, division or cuttings, and planted directly into the soil. Asparagus densiflorus are also very drought tolerant (fleshy roots). The variegated Plectranthus madagascariensis ‘Lynne’, Plectranthus verticillatus and Plectranthus malvinus with fleshy leaves and rapid growing ground covers.
Bush lily | Clivia miniata
For very hot dry Bushveld conditions, Plectranthus neochilus, Plectranthus spicatus and the succulent mother-in-law's tongue are ideal (Sansevieria aethiopicum, Sansevieria hyacinthoides). Plantings can be complemented with the spotted leaved aloes (Aloe greenii and relatives) which forms carpets below bushveld trees, are well suited. The bushveld orchid Eulophia petersii in groups below trees.
Perennials and bulbs
There are many forest-adapted bulbous species. Once established, they are long-lived and drought tolerant. Solitary forest crinum (Crinum moorei), forest powder brush (Scadoxus multiflorus and Scadoxus membranaceus) and falling stars (Crocosmia aurea).
Crinum lily | Crinum moorei
Forest climbers cover shrubs, dead shrubs and can be used on shady fences etc. sickle leafed asparagus (Asparagus falcatus) is ideal for shady fences, the latter forming an un-penetrable thorny fence). The asparagus fern (Asparagus plumosus) with fern-like spreading foliage and without spines. The wild jasmine (Jasminum multipartitum) another excellent example. The binder (Acridocarpus natalitius) is a slow-growing but long-lived climber bearing leathery leaves and yellow flowers during summer. It is excellent for shady fences. Senecio macroglossus and Senecio bryoniifolius are two others climbers bearing succulent leaves and daisy-like flowers great for shady areas. The cat-thorn (Scutia myrtina) scrambling spiny shrub excellent as barrier planting in shade.
Wild jasmine | Jasminum multipartitum
Ferns vary from the single-stemmed tree ferns to smaller maidenhair and others. They generally require sufficient moisture year-round. The seven weeks fern (Rumohra adiantiformis) can tolerate dry conditions to some extent.
Various epiphytic orchids grow well on tree bark in shady conditions. The largest the Mopane orchid (Ansellia africana) which can be established on a tree branch. They are very slow growers but with great long term results. Once established need little care. They live from debris accumulation, however, feeding would increase performance.
Mopane orchid | Ansellia africana