Diastella divaricata subsp. montana
Diastella divaricata (P.J.Bergius) Rourke subsp. montana Rourke
Common names: mountain silkypuff
A sprawling, rounded shrub with small pink inflorescences almost all year round, ideal for fynbos gardens, hanging baskets and containers in full sun.
Diastella divaricata subsp. montana is small, evergreen, fynbos shrub that grows about 0.5 m high and spreads about 2 m in diameter. It has a creeping stems that hang down when planted in pots and spread widely when growing in the open ground. Leaves are long, narrow, lanceolate to elliptic, 10-18 mm long and 1-7 mm wide. They are arranged alternately, and are hairy with reddish margins on the new growth, but this reddish margin disappears as the leaves mature. The leaf tip is pointed with a red dot on the tip.
Diastella divaricata subsp. montana produces small, pink flowerheads. The involucral bracts and perianths are both pink and become papery with age (never becoming woody). The styles are 8–10 mm long and exserted 5 mm above the ovary . Mountain silkypuff flowers year round, with a peak in spring, from August to September. Each flower occasionally makes one nut-like seed, and releases the fruit 1–2 months after flowering. The fruit is egg-shaped, 4–6 mm long, greyish or white, and is hardly seen on cultivated plants.
Diastella divaricata subsp. montana is very similar to D. divaricata subsp. divaricata, the Peninsula silkypuff. However, the two subspecies differ by their geographical distribution, in leaf size and shape and the pubescence of the base of the styles. Subsp. divaricata has short, oval or rounded leaves of 2–10 mm long and 2–7 mm wide and is restricted to the Cape Peninsula.
According to the Red List of South African plants, checked April 2017, Diastella divaricata subsp. montana is assessed as Vulnerable (VU). It is estimated that the wild population has decreased by 30% because some of its habitat has been lost over the past 60 years to pine plantations, and invasive alien pines and hakeas.
Distribution and habitat
Diastella divaricata subsp. montana occurs naturally from the Wemmershoek Mountains to Villiersdorp, western Riviersonderend Mountains, Hottentots-Holland, Greenland, Kleinmond and Kleinrivier Mountains, growing in sandstone fynbos on the southern, sandstone slopes, in a cool and moist environment.
Derivation of name and historical aspects
Diastella is derived from the Greek word diastellein, which means ‘to separate’, referring to the soft, silky-haired perianth segments which are free to the base. Montana is from the Latin word montanus, which means 'of mountains', referring to its habitat.
Diastella is one of 14 genera of the Proteaceae family. The genus Diastella is endemic to the Cape Floristic Region. It is a small genus that comprises of 7 species. All are shrublets and almost all species are threatened. There are the northern silkypuffs, D. parilis [Critically Endangered] and D. myrtifolia [Critically Endangered] and the southern silkypuffs, D. buekii [Critically Endangered], D. fraterna [Rare], D. proteoides [Critically Endangered], D. thymelaeoides subsp. meridiana [Vulnerable], D. thymelaeoides subsp. thymelaeoides [Near Threatened], D. divaricata subsp. divaricata [Rare] and this subspecies. The southern silkypuffs do not produce nectar, whereas the northern silkypuffs have floral nectaries.
Diastella divaricata subsp. montana produces smooth, nut-like seeds with an elaiosome. The seeds are taken by ants and stored underground in their nests. The ants feed on the elaiosome, but leave the seed unharmed. Usually one fruit develops in each flowerhead and drops to the ground when matured, within a period of 2 months, and will germinate the following autumn if not removed by ants or destroyed by rodents. No records were made for pollinators, though it is believed to be pollen-collecting bees.
Mountain silkypuff is killed by fire and regenerates by seed (reseeder).
Diastella divaricata subsp. montana is an excellent plant when cultivated in a container or te garden, preferabley in a rock garden, retaining wall or fynbos garden. Mountain Silkypuff has a naturally spreading or cascading habit and develops a wonderful rounded shape.
Growing Diastella divaricata subsp. montana
Diastella divaricata subsp. montana is easily propagated by cuttings and seed. Select the cuttings from healthy plants. Take heel or tip cuttings of semi-hardwood 30–70 mm long in autumn and spring. Treat with a rooting hormone to stimulate rooting. Dip the cutting in the rooting hormone for at least 5 seconds. Place your cuttings in a well-drained and aerated medium of 70% perlite and 30% fine bark or use coarse sand and finely milled, pine bark sowing medium. Insert the cuttings in the multitrays with a space between each cutting to allow air circulation, and place them on the heated benches of 25ºC under intermittent mist. Regularly treat the cuttings with fungicide to prevent fungal infection. Remove the dead leaves and wilting cuttings until your cuttings are rooted. Move the rooted cuttings to the hardening-off house for about 2 weeks and transfer the cuttings into small nursery plastic bags using a fynbos mixture of well-drained, acidic medium of fine bark, coarse sand and finely milled, pine bark.
The seeds are not easy to collect and itis time-consuming, therefore most cultivation is done by cuttings. Seed must be treated with a fungicide to prevent pre-and post-emergence damping-off. Treat your seed with a dusting systemic fungicide containing the active ingredient, metalaxyl. The seed is sown in late summer or early autumn. Use a well-aerated and well-drained potting or sowing medium and treat with smoke. Lay the seed trays under the plastic tent and the pipe, in the smoke of burning, fynbos plant material. Smoke-plus seed primer packets are also available to use and can be ordered from the Kirstenbosch National Botanical Garden Seedroom.
Place the seedlings or cuttings under the shade net in the nursery until they are ready to be planted into the garden, after a period of 2 to 3 years. Net shade reduces the direct sun which can dry out the soil in the plastic bags and can also prevent scorch. Diastella divaricata subsp. montana is a water-wise shrub that will need to be watered for about 2 to 3 years, to establish the roots. Plant the seedlings in sandy acidic soil with between 5–7 pH levels.
Keep the soil moist during the hot dry season by mulching your bed about 5 mm thick. The mulch will keep the roots cool, keep moisture to the soil and reduce the growth of weeds. Chipping mulch is recommended, as they break down very slowly and also releases small amounts of nutrients to the plant. Diastella dicaricata subsp. montana does need pruning to keep the rounded shape and nice cascade in a container.
It is not affected by serious insect pests, however, seedlings are highly susceptible to pre- and post-emergence damping-off fungi.
Diastella divaricata subsp. montana can be grafted on the scion of hybrid ‘Veld Fire’, a cross between Leucospermum glabrum and L. conocarpodendron subsp. conocarpodendron. The grafted plant can sustain the longevity and resistance of the plant in the garden.
- Adamson, R.S. & Salter, T.H (eds). 1950. Flora of the Cape Peninsula. Juta, Cape Town.
- Brown, N.A.C. & Duncan, G.D. 2006. Grow fynbos plants. Kirstenbosch Gardening Series. South African National Biodiversity Institute, Cape Town.
- Duncan, G., Brown, N. & Nurrish, L. 2013. Grow proteas. Kirstenbosch Gardening Series. South African National Biodiversity Institute, Cape Town.
- Paterson-Jones, C. 2000. The protea family in southern Africa. Struik Publishers, Cape Town
- Protea Atlas Project: Meanings of scientific names. http://www.proteaatlas.org.za/meanings.htm. Accessed on 2017/03/29.
- Rebelo, A.G. 2001. Proteas. A field guide to the proteas of southern Africa, edn 2. Fernwood Press, Vlaeberg, Cape Town.
- Rebelo, A.G. et al. 2006. Diastella divaricata (P.J.Bergius) Rourke subsp. montana Rourke. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2017/05/01
- Vogts, M. 1982. South African's Proteaceae: know them and grow them. Struik, Cape Town.
Kirstenbosch National Botanical Garden
Plant Type: Shrub
SA Distribution: Western Cape
Soil type: Sandy
Flowering season: Sporadic/All year
Flower colour: Pink
Aspect: Full Sun
Gardening skill: Average