Drosanthemum hallii
L.Bolus

Family: Mesembryanthemaceae
Common names:
None recorded

Gardeners will welcome the bright yellow, showy flowers of Drosanthemum hallii with open arms. This shrubby perennial gives a lustrous display of flowers in early spring, and will attract many insects.

Description
Drosanthemum hallii is a low-growing shrub with an oval shape and a fibrous root system that allows it to take up water quickly. The branches can grow up to 270 mm long with 10–45 mm long internodes.Papillae occur on the reddish-brown bark on the younger stems as white distant dots in the dry state, which later becomes hairy or scaly as the plant grows older.

Stems, leaves and fruits

The attractive, 10–26 mm long, oblong, roundish leaves are also covered with glistening papillae. D. hallii has bright yellow solitary flowers with outer petals 18 mm long and inner petals 8 mm long. In the centre of the flower are numerous filamentous (thread-like) white or pink, as well as a few true black staminodes (sterile stamens) 0.5–1.5 mm broad and 2 mm long; the stamens are arranged in a cone; and the glands of the nectary are inconspicuous.

Flowers and close up of centre

The capsules of this species are 4–6-locular with valve wings and expanding keels; the tubercle is very small or absent. The light brown seeds are fairly small and rough, with ribs and tubercles.

It is fast-growing and flowers from September to October.

Conservation status
Drosanthemum hallii is classified as Endangered, according to C. Klak and D. Raimondo (Red Data list). Major threats include vineyard expansion and invasive alien species. The Karoo Desert National Botanical Garden, in association with the Millennium Seed Bank Project, is undertaking key conservation strategies through seed banking and propagation to conserve this species.

Distribution and habitat
Drosanthemum hallii is known from the Worcester–Breede River valley in the Western Cape and prefers the temperatures of the winter-rainfall region. It grows usually on north-facing slopes on shale-sandstone transition soils.

Growing in habitat

Derivation of name and historical aspects
Drosanthemum comes from the Greek word ‘ drosos ', which means dew, and ‘ anthemon' , which means flower. All of the above refers to the glittering papillae on the leaves and young stems. The specific name honours Harry Hall, famous plant collector and for two decades curator of the succulent collection at Kirstenbosch. This genus is also referred to as the dew flowers. There are several other drosanthemums suited to cultivation such as D.bicolor, D.micans, D speciosum, D.floribundum.

Ecology
Drosanthemum hallii flowers during the warm period of the day, thus attracting many insects and bees as pollinators. Bees are specifically attracted to the showy yellow flowers. This species has very fleshy leaves that store water and food during the dry and hot dormant period of the year. Mature seeds are dispersed ina unique way: The capsules are adapted to dry conditions and only open when conditions are favourable. They are known as hygrochastic capsules, which open when it rains, and the water droplets then splash the seeds out of the capsule onto the ground, guaranteeing a higher rate of germination.

The family Mesembryanthemaceae is one of the largest in southern Africa and occurs in a variety of vegetation types.

Uses and cultural aspects
There are no medicinal uses of this plant and few are seen in gardens as it is not well known. This species, however, would make a great border along pathways and could also be used in pots, rockeries and any water-wise garden.

Growing Drosanthemum halli

Drosanthemum hallii can easily be grown from seed and cuttings. Harvest seeds in late summer (January to February) and sow seeds in autumn (March to April). Use a sterilized shallow seedling tray and fill it up with a mixture of 60% coarse river sand and 40% sieved compost. Sow seeds on top of the mix, ensuring that they are spread evenly. Cover with a fine layer of sand, and then water, using a mist sprayer. Seedlings will germinate within 2 weeks. Propagation by cuttings is also easy. Take cuttings when the plant is in growth (June to August). Use only soft tip cuttings and insert them into coarse river sand. Always use sterilized equipment and growing mediums. A rooting hormone can also be applied to the end of the cutting for optimum results. Water seeds and cuttings every morning and keep moist and in a humid area until transplanting. Transplanted seedlings and cuttings should be placed in a medium with a high compost ratio and in a sunny area.

Drosanthemum hallii does well in groups and is also famous as a plant for water-wise gardens, as it is drought-tolerant. Use it as a focal point during spring, as the colour will amaze any visitor.

References and further reading

  • Herre, H. 1971. The genera of the Mesembryanthemaceae . Tafelberg, Cape Town.
  • Jacobsen, H. 1970. Lexicon of succulent plants . Blandford Press, London.
  • Schwantes, G. 1957. Flowering stones and mid-day flowers . Ernest Benn, London.

 

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Karoo Desert National Botanical Garden

April 2013

 

 

 

 

 

 

To find out if SANBI has seed of this or other SA species, please email our seedroom.

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


 

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