This water-wise, small aloe-like plant with warty tubercles on the leaves makes a very interesting coffee table plant.

Description
The plant is a succulent that looks like a miniature aloe. It grows in a compact rosette, is more or less stemless, and approx. 250 mm tall. Leaves are 140 x 20 mm. What makes this plant interesting are the raised , ± round, greenish white tubercles that are very conspicuous on the underside of the leaf surface. The flower spike is approx. 400 mm tall. The aloe-like flowers are brownish white in colour and waxy in texture. Flowering time is early summer, October/November. Seed ripens in February/March of the following year.

The plants live for about 30 to 40 years if they are looked after properly. Haworthia maxima is not endangered. It grows relatively slowly from seed and it takes about 5 years for a plant to reach flowering maturity.

Distribution
The plant occurs in Karroid Broken Veld and is common in the Worcester/Robertson Karoo, particularly around Worcester, Robertson, Ashton, Bonnievale, Montagu and Drew.

The plant occurs in a winter rainfall area of Western Cape, which experiences mild frost, -2°C. Summers are hot, up to 44°C. Rainfall varies from 150 mm (Worcester area) to 350 mm (Montagu area).

Derivation of name and historical aspects
The plant was widely known Haworthia margaritifera and H. pumila, but has recently been re-instated as Haworthia maxima. As this is the largest of the haworthias, this is a most appropriate name. The nomenclature is complicated, see Mottram 2000 for details. There are 105 species including varieties of the genus Haworthia. The genus is named after English botanist and writer on succulents, Adrian Hardy Haworth, 1768-1833.

The genus Haworthia is more or less restricted to South Africa with one species occurring in Namibia and one species occurring over the Lebombo Range into Mozambique. The highest concentrations of Haworthia species are in the eastern and southern Cape.

Ecology
Pollinators include bees, moths, bumble bees, the Malachite and the Lesser Doubled-collared Sunbirds.

Uses and cultural aspects
The leaves of the plant are mashed and used by traditional healers as soap. The leaves crushed and broken up can also be used as a poultice. Fears that it is being over-collected in the wild are emerging. Horticultural uses include planting in rock gardens and they also make wonderful miniature succulent pot displays. In larger gardens they can be used with great effectiveness as mass plantings in a bed.

Growing Haworthia maxima

Propagating from fresh seed is easy. Seed older than 18 months in most cases is not viable, unless kept under cool, dry conditions. Haworthia seed is similar to aloe seed, but much smaller.

Sow the seeds in April, which is when the first rain normally falls in the winter rainfall Karoo. Sow in well-drained, rich loamy soil, sow no deeper than 30 mm. Water enough to keep the soil merely damp, ensure the growing medium is not soggy. A very wet growing medium will cause damping-off of the seedlings or result in the seeds rotting.

Viable seed should germinate with 21 days. Once the seedlings are strong enough, after about one year, transplant into containers. Initially keep strong sunlight off the young plants. Once the plants have adapted to stronger light they can be planted out in the open.

Pests include mealie bug, aphids and red spider mite. Aphids can be controlled by spraying with washing-up liquid soap. A mix of 10 ml liquid soap to 1 litre water is recommended. Mealie bug, can be effectively controlled by spraying with a mixture of methylated spirits and water. A mix of 10 ml to 1 litre water is recommended. Red spider mite is not so easy to eradicate, use recommended miticides for this purpose.

Plants can be fed with 2:3:2, bone meal and seaweed extracts.

References

• Bayer, M.B. 1999. Haworthia revisited. A revision of the genus. Umdaus Press, Pretoria.
• Bayer, M.B and van Jaarsveld, E. 2001. Haworthia. in Illustrated Handbook of Succulent Plants: Monocotyledons. Springer, Berlin.
• Mottram, R. 2000. Haworthia pumila, margaritifera, or what? Haworthiad Vol.14(1)22-24pp.

Ian Oliver
Karoo Desert NBG
July 2003