Platylophus trifoliatus (L.f.) D.Don
Common names: white-alder, white-els (Eng.); witels, witelsboom, witte-els, witte-elsboom, witte-elshout (Afr.) Synonyms: Weinmannia trifoliata L.f.; Trimerisma trifoliata
SA Tree No: 141
Finding large specimens of this tree in their habitat, may make you think that you have wandered into a forest inhabited by the characters found in ‘The lord of the rings’.
A small to large, evergreen tree, which may reach 30 m tall. Stems of really old trees may take on rather gnarled and grotesque forms. The bark is vertically fissured, greyish initially, becoming brownish with age.
Many of the trees are multi-stemmed as a result of the trees ability to coppice. Single clean-stemmed trees are seldom found. The wood varies in colour from pinkish brown or yellowish, with darker markings, to dark brown. The wood is medium-hard and medium heavy. Old trunks that are gnarled, have an attractive bird’s eye grain.
The leaves make this tree easily identifiable, as this is the only tree species in South Africa which has opposite, compound trifoliate leaves, with serrated (toothed) margins. The leaf stalk may be as long as 40 mm and the leaflets are sessile (no stalk) and lance-shaped. The veins are clearly visible on both the upper, dark green surface and the paler surface below.
Flowering is in midsummer, from December to February; the many small, sweetly scented flowers are white to cream-coloured and loosely clustered together on long-stalked bunches, emanating from the upper leaf axils. The calyx lobes and petals are 4 or 5, with 8–10 stamens. Fruits are flattened, small capsules (about 10 mm long), pale yellow or russet to dark brown, with a persistent style at the tip. Each 2-chambered, indehiscent (fruits that do not open to shed their seeds) capsule, contains 2, red-brown seeds.
Slow growing, these trees may become hundreds of years old, as a result of being able to re-sprout when the stems or branches get damaged.
According to the Red List of South African plants, Platylophus trifoliatus is assessed as Least Concern (LC).
Distribution and habitat
Endemic to the Eastern and Western Cape, in moist to wet, protected forested kloofs, in an area stretching from Piketberg to Humansdorp, mostly along rivers and streams. They have high moisture requirements and favour areas which are sufficiently humid and wet.
Growth differs depending on where the trees are growing. For example tall white-alders may be found in forests, classified as moist high-forest and as smaller, bushy trees, in wet forest, classified as wet high-forest, very wet scrub-forest and very, very wet scrub. White-alder occurs most frequently in the southern Cape forests.
From its distribution, it would seem that this tree will grow in moist to wet forested areas, with either a winter rainfall or all-year rainfall pattern.
Derivation of name and historical aspects
The name Platylophus derives from platys, the Greek word meaning ‘broad’ and lophos, ‘a crest’, alluding to the compressed fruit capsules. The trifoliate leaves give rise to the species name, trifoliata.
The white-alder and the rooiels or red-alder (Cunonia capensis) are the only two representatives of the Cunoniaceae family in southern Africa. The family consists of 27 genera and about 280 species, mainly in tropical and temperate regions of the southern hemisphere. The closest relative of Platylophus trifoliatus, is a species of Andropetalum, a native tree endemic to Tasmania.
The vernacular name witels, meaning white-alder, was first recorded by Thunberg in January 1774, in the area of the indigenous Grootvadersbosch forest, near Swellendam. The vernacular names allude to the similarities of the wood to the alders of Europe, the Alnus species. The related rooiels, Cunonia capensis, has similar wood, only of a deeper red to light brown, sometimes with white flecks or black markings. The wood of the rooiels is also harder and heavier than that of the witels. Another tree, commonly named the rock-alder or klipels, Canthium mundianum, also has a wood similar to the European alders but belongs in a different family, and the word klip, refers to the hardness of the wood and not to a rocky habitat.
This tree was illustrated in the Codex Witsenii, a collection of over 1 500 paintings put together by the Dutch Statesman, Nikolaes Witsen (1641–1717), most of which depicted plants from the Cape Peninsula. Copies of watercolour sketches by Clemenz Heinrich Wehdermann (1762–1835), are housed in the British Natural History Museum.
Honey bees and other insects are greatly attracted to the tree, as it produces copious nectar. The bees act as pollinators for these trees. Birds and wild pigs eat the fruit and seeds. Some years ago, in the Harold Porter National Botanical Garden, baboons ripped off large chunks of the outer bark, and scraped off the inner bark with their teeth. This is the only time this has been noticed on the trees there and it is unknown why it would have been done.
Trees can grow to be very old, as they have a survival strategy of coppicing (resprouting) when the trunks are damaged, either by being broken off or being felled, or from the exposed root disc, when trees are blown over. Numerous shoots grow up and may grow to be new trunks, thus allowing the trees to regenerate time after time. The young shoots are much favoured by Bushbuck (Tragelaphus scriptus sylvaticus), which crop the shoots on a regular basis, thus increasing the number of new shoots and eventually producing a ‘cabbage head’ as a sustainable source of food. Eventually the stump becomes so large, that the buck can no longer reach the upper shoots, which can then become new stems. The stinkwood (Ocotea bullata), uses the same method of regeneration as the white-alder. A fern, Elaphoglossum conforme, can often be found growing on the old tree trunks of the white-alder.
The nectar of this tree collected by bees, makes a delicious, much sought after honey. It is considered to be the best bee tree in the areas in which it grows. As it has a fine, even grain, the sweetly scented wood, which is worked quite easily, is used for paneling, furniture, boat keels, boxes and picture frames, interior cabinet construction, veneers and window and door frames. Wood from trees growing in wetter areas, is more durable than the wood from trees growing in drier areas. The durable nature of the wood in humid or wet conditions, makes it particularly suitable for boat building. In 1774, Thunberg recorded the white-alder being used for boards and planks in wagons, and sometimes for cupboards, as well as boards for shoemakers.
Honey farmers who have the right humid and wet conditions to grow these trees, would be providing their bees with a wonderful resource.
Growing Platylophus trifoliatus
In Eve Palmer and Norah Pitman’s first volume of Trees of southern Africa, the following information is given: ‘Seedlings of the White Alder are rare. Birds destroy quantities of seed and wild pigs destroy the capsules. Mr Laughton, while Forest Research Officer at Knysna, found that the sowing of 25 muid sacks of seeds over a period of 25 years did not result in the germination of more than 250 seedlings. A muid sack contained 109.1 litres of seed! ’
Rachel Saunders of Silverhill Seeds supports this finding, 'the main problem is that the seed that is produced is usually about 90% empty. We often find trees with “seed” but when you examine them, you cannot find any endosperm at all.' (R. Saunders, pers. comm.)
Anthony Hitchcock, Nursery Manager at Kirstenbosch National Botanical Garden, has contributed the following information on the growing of Platylophus trifoliatus:
‘I have not had experience of growing this species from seed. If I did I would sow in the warm summer months and smoke treat as it is a tree occurring in the fynbos. I often find non-core fynbos species from this region responding to smoke. I would recommend keeping the seed under glass to have higher humidity based on the natural habitat. I have seen seedlings growing out of moss on the embankments of streams where it is moist and humid. The seed is fine and probably has little reserves. Another intervention would be to dust the seed with a pre-emergence damping off fungicide to prevent rotting/infection.’
‘I have grown them successfully from cuttings I collected in Bain’s Kloof. I collected in mid-summer on New Year’s day when it was hot, but I kept the cuttings in cool shade next to the stream amongst the boulders and under shade of trees. They were at no time exposed to stress. I was very careful in selecting the cuttings. The tree was mature and in good condition. I looked for cuttings that showed active growth which I found near the ends of the branches. Most of the tree presented material where the tips were leafy, but the stem was short and often curved, with closely packed nodes and short internodes. I avoided these and looked behind the terminal growth for side shoots that were straight, with longer internodes and showed active and hardened-off growth, with the wood having changed from green to light brown. It was easy to detect these more vigorous, actively growing shoots and they were straight, which is necessary for better quality plants. Where possible, I selected heel cuttings, but tip cuttings also work. The cuttings were rooted in 50:50 milled bark and polystyrene which allows for good aeration. Used Seradix 2 rooting powder 2 000 ppm for semi hardwood cuttings and placed them on a heated bench 25 ºC, under mist to prevent desiccation.’
Most people do not have access to these facilities, so alternatively place in a pot just large enough for the cutting and using the same rooting material and hormone. Cover the tree cutting with a clear plastic bag and seal with an elastic band. You can use wire to support the plastic and keep it away from the leaves. Place out of the direct sun, in a warm, shaded place and regularly check that the rooting medium is not drying out and remove any dead leaves. You can also apply a broad spectrum fungicide drench to prevent infection. Cuttings are known to root well, using this method, but it takes longer. When the cutting starts to show signs of growing, you may assume that roots have begun developing. Check the cutting for roots and if well developed, begin the hardening-off process, by first making a slit in the plastic to allow for more air circulation. A week later, open the opening in the plastic bag further and then remove after about 2 weeks. Close up the plastic bag and slow the process if you notice the plant is showing signs of stress or desiccation. It is recommended that you water in Kelpac to feed the roots and reduce stress. Once the plant is hardened off, re-pot into a well-drained potting medium that does not contain manure. Conifer-growing medium is ideal and available from some retailers. Grow the young tree on in a protected place where it gets morning sun, but not full day or hot afternoon sun, or under 40% shade cloth. Feed regularly with an organic fertilizer following the instructions.
If the cutting develops callus and no roots, then wash the cutting and nick the callus with a clean blade and apply a broad spectrum fungicide. Replace in a fresh batch of rooting medium and start the process again, whether under plastic or mist. Experience has shown that callus treated this way, most often results in vigorous root development.
The collection from Bain’s Kloof rooted very well, over 80%, and the plants are vigorous. The plants from cuttings are erect and sturdy growing and have smaller leaves than the Betty’s Bay form.
Adam Harrower reports that cuttings he collected and others by James Deacon, rooted poorly. Adam took similar cuttings and also cuttings from material suckering from the base of the tree from the plant in Harold Porter, the kloof above and to the right of the Garden. James Deacon from the same area, but we cannot be sure of the quality of James’ collecting. The Betty’s Bay plants that rooted, have struggled being floppy in growth habit and had to be staked, but still flopped above the stake. The leaves were in poor condition being yellowish and tending to become brown on the edges. Adam wonders if they are not infected with broad mite, which we have identified as a major problem in this garden.
Timing: ‘I always recommend propagating trees in summer when it is warm and they are actively growing even if the tree comes from the Western Cape.’
- Bean, A. & Johns, A. 2005. Stellenbosch to Hermanus South African wild flower guide 5. Botanical Society of South Africa, Cape Town.
- Coates Palgrave, K. 1983. Trees of southern Africa. Struik, Cape Town.
- Manning, J. & Goldblatt, P. 2012. Plants of the Greater Cape Floristic Region 1: the Core Cape Flora. Strelitzia 29. South African National Biodiversity Institute, Pretoria.
- Palmer, E. & Pitman, N. 1972. Trees of southern Africa . Balkema, Cape Town.
- Raimondo, D. et al. 2009. Red list of South African plants. Strelitzia 25. SANBI (South African National Biodiversity Institute), Pretoria.
- Smith, C.A. 1966. Common names of South African plants. Memoirs of the Botanical Survey of South Africa No. 35. Government Printer, Pretoria.
- Van Wyk, B. & Van Wyk, P. 1997. Field guide to trees of southern Africa. Struik Publishers, Cape Town.
- Von Breitenbach, F . 1974. Southern Cape forests and trees. The Government Printer, Pretoria.
Harold Porter National Botanical Garden
with propagation information by Anthony Hitchcock
Kirstenbosch National Botanical Garden
Plant Type: Tree
SA Distribution: Eastern Cape, Western Cape
Soil type: Loam
Flowering season: Early Summer, Late Summer
PH: Acid, Neutral
Flower colour: White, Cream
Aspect: Shade, Morning Sun (Semi Shade)
Gardening skill: Challenging