Leucadendron rubrum

Burm.f.

Family : Proteaceae
Common names
: spinning top conebush (Eng.); tolletjiesbos, waretolbos (Afr.)

Leucadendron rubrum
Leucadendron rubrum flower heads

Leucadendron rubrum is not a flowering show stopper. It is an interesting shrub producing wonderful, brightly coloured cones looking like spinning tops. This is a great plant for plant collectors looking for something slightly different to display in their garden.

Description
Leucadendron rubrum is an erect shrub growing to 2.5 m tall. Plants develop from a single-stemmed base, with male plants being bushier and having smaller leaves than female plants.

Young branches in male plants are flexible, sometimes a purplish colour, and covered with fine hairs. As they mature they become smooth. Young female branches are much hairier than the male branches but are fewer in number and fairly stout.

Leaves are covered with silver-white hairs when soft and young. On maturing they lose most of the hairs and are a green-grey colour. The female leaves are twisted near the base, which, together with the shape of the female cone imitates the motion and shape of a spinning top.

Male and female flower heads are clustered along the ends of branches. Male flower heads are very small, measuring about 11 mm long but are a vibrant bright yellow, and flower in a golden plume. Female flower heads form a cone about 40 mm long. The yellow female stigmas pop out at the top of the cone in a tuft. The bracts forming the cone are a colourful mix of yellow, green, blue and red.

Leucadendron rubrum female flower head Leucadendron rubrum male flower head
Leucadendron rubrum
female flower head
Leucadendron rubrum
male flower head

Flowering occurs in August and September and seeds ripen a few months later. Seeds are 8 mm long, wedge-shaped and hairy.

Plants grow relatively quickly and will flower after three years if grown from seed.

Conservation status
Leucadendron rubrum is listed as Least Concern (LC), meaning it is not currently threatened owing to its wide distribution range.

Distribution and habitat
Leucadendron rubrum occurs across most of the Fynbos biome from the Bokkeveld escarpment in the north, Table Mountain in the southwest, to the Baviaanskloof Mountains in the east. Although it occurs across a large area, L. rubrum does not show much variation in habit. It grows on dry slopes on Cape Granite or Table Mountain Sandstone at an altitude of between 250 and 1500 m.

Derivation of name and historical aspects

Leucadendron rubrum male shrub
Leucadendron rubrum male shrub

The Proteaceae family is large, consisting of about 1 400 species. The Leucadendron genus contains about 83 species; which, apart from 1 outlying species and 2 outlying subspecies, are all confined to the southern and southwestern Western Cape.

The genus name is composed of leucos meaning white and – dendron meaning tree. This refers to the iconic Silver-tree (Leucadendron argenteum) on which the genus was based. Early Dutch settlers originally referred to the Silver-tree as the Witteboom or ‘White tree'.

It is unclear what the specific name rubrum (meaning red) refers to; possibly to the purplish bracts on the female flowerhead.

Leucadendron rubrum was first drawn and recorded in the early 1700s.

Ecology
Male Leucadendron plants produce lots of pollen that is blown by the wind onto the female flowers. Pollination occurs and seeds develop inside the cone on the female plant. Seeds are retained inside the cones for a number of years or until the plant is killed by fire. Each seed has a hairy parachute attached to it, so when the cone opens they float away carried by the wind away from the mother plant.

Uses and cultural aspects
Female cones are sought after for use in dried flower arrangements.

Leucadendron rubrum female shrub
Leucadendron rubrum female shrub

Growing Leucadendron rubrum

Leucadendron rubrum can be propagated from cuttings or seed. Both methods are prone to problems, as the hairs on the leaves of cuttings as well as the downy hairs on seeds tend to collect water, making the plants more susceptible to rotting. Treat material regularly with a fungicide and water sparingly.

Make cuttings from December to March (summer to autumn). The cuttings should be semi-hardwood, 60–100 mm long, and taken from the current season's growth. Dip the cuttings into a rooting hormone solution or hormone powder and plant into a medium of 50% polystyrene and 50% finely milled bark. Place in a growing house with bottom heat (25 ºC). Once the roots are well developed, remove from bottom heat and harden off for three weeks. Plant the cuttings into small bags and grow on until ready to plant into the garden.

Sow seed in April when the days are warm and the nights start to cool down (late summer to autumn). Dust the seed with a systemic fungicide. Sow on a well-drained medium consisting of 1 part loam, 1 part bark, and 2 parts sand, firm down and cover with a layer of sand or finely milled bark. Seed can be sown in an open seedbed, or in a seedtray placed in a sunny position. Germination begins after two to three weeks. Once two true leaves have grown, prick the seedlings out into small bags. Place the seedlings in a lightly shaded area with good air circulation. When plants are ± 50–100 mm tall, or after one year's growth, they can be planted into the garden. Nipping out the tips of the seedlings will encourage branching and produce a neater shrub.

The best time to place the young plants in the garden is just before the rainy season. This enables plants to establish themselves and send down deep roots before the hot, dry summer season. Leucadendron rubrum requires a hot, sunny, exposed situation with well-drained soil. Add a scoop of well-decomposed compost at planting and water well for the first year.

Once members of the protea family become diseased they are very difficult to treat, and it is better to prevent disease, rather than try to cure it. Make sure the environmental conditions are correct. This includes getting direct sunlight for most of the day, a well-drained soil which does not stay saturated and will not stagnate, and good air circulation ensuring that the above-ground parts of the plant dry quickly after watering. It is also important to ensure that the soil stays cool in the hot months and that roots are not disturbed by digging. A thick layer of mulch or groundcover planting can be used to keep the soil cool and prevent moisture loss. If any of these factors are not correct, the plants become weakened and stressed, and you can be sure to attract some form of pest or disease.

Leucadendron rubrum is very well suited to a hot dry fynbos garden. The grey-green foliage provides a muted backdrop or good filler planting between other brightly coloured flowering fynbos shrubs such as Leucospermum tottum, Erica baccans, Agathosma ovata and Euryops pectinatus.

References and further reading

  • Eliovson, S. 1979. Proteas for pleasure. MacMillan South Africa Publishers, Johannesburg.
  • Goldblatt, P. & Manning, J. 2000. Cape plants. A conspectus of the Cape flora of South Africa. Strelitzia 9. National Botanical Institute, Pretoria & Missouri Botanical Garden Press, Missouri.
  • Jackson, W.P.U. 1990. Origins and meanings of names of South African plant genera. University of Cape Town Printing Department, Cape Town.
  • Powrie, F. 1998. Grow South African plants. National Botanical Institute, Cape Town.
  • Rebelo, A. (Tony). 2001. Proteas. A field guide to the proteas of southern Africa, edn 2. Fernwood Press, Cape Town.
  • Vogts, M. 1982. South Africa's Proteaceae, know them and grow them. Struik, Cape Town.
  • Website: Plants of southern Africa : an online checklist. http://posa.sanbi.org.
  • Williams, I.J.M. 1972. A revision of the genus Leucadendron (Proteaceae). Contributions from the Bolus Herbarium 3. University of Cape Town.

 

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This page forms part of the South African National Biodiversity Institute's plant information website www.plantzafrica.com.


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