Coleonema album

(Thunb.) Bartl. & J.C. Wendl.
Family: Rutaceae (citrus family)
Common Names:
Cape May, white confetti bush (English), aasbossie, klipboegoe (Afrikaans)

Coleonema album

This decorative shrub with dainty, small white flowers and sweet, honey smell make this buchu an ideal garden plant and interesting specimen for floral arrangements.

Description
Coleonema album an erect, much-branched and compact shrub grows to a height of 2 m. This fragrant buchu is finely branched and new shoots develop at the tips of old branches. Branching occurs from the base of the shrub. Bark is greyish-brown, rough with horizontal leaf scars. The inflorescence is solitary, axillary and crowded at the branch tips. Closed flower buds are pinkish tinged and appear white when open. Flowers are small, white, 6-7 mm in diameter with a dark green disc at the centre. Crowded at the branch tips are 5-11 blooms. The flowers are carried in such profusion that the bush is a cloud of white when in flower and attracts bees and butterflies. It flowers from May to November.

Leaves are needle-like / linear-oblong are 12-13.5 mm x 1.3-1.5 mm broad. Oil glands are visible on the reverse side of the leaves. The leaves when crushed have a characteristic sweet smell. Ripe fruits may be found up to end of November. The fruit is 5-lobed and ripe seed are ejected by a catapult mechanism. Regeneration takes place from seed.

Distribution
Coleonema album occurs from Saldanha Bay to the Cape Peninsula and as far east as Bredasdorp.

Bush growing in KirstenboschThis buchu appears to be very much a coastal plant, able to withstand strong coastal winds. The only population at any great distance from the sea lies at the southern end of the Bredasdorp Mountains about 19 km from the sea. Plants are found growing amongst outcrops of rocks of the Table Mountain Sandstone series or of the underlying Cape granite, but never on the coastal limestone of the Bredasdorp Series. Plants grow at sea level and up to a maximum altitude of 750 m on Table Mountain.

Derivation of name and horticultural aspects
From the Greek koleos, sheath, and nema, thread / filament. The filaments of the sterile stamens are enfolded in the channel of petals.

There are eight species found in the genus Coleonema, which occur in Western Cape and Eastern Cape. This genus belongs to the Rutaceae family also known as the citrus family. The confetti bush, Coleonema pulchellum, an erect shrub, 800 mm -1 m in height, bears pink flowers from May to October, also belongs to this genus, as does C.aspalathoides.

Ecology
The conspicuous white flowers and the nectariferous disc indicate that pollination is most probably effected by insects.

Uses and cultural aspects
It is an excellent coastal plant and can be used as a topiary specimen. The aromatic leaves containing essential oils are used by fishermen to remove the odour of redbait (aas) from their hands, hence the common name.
Campers rub the leaves onto their bedding to keep ants and mosquitoes away. The leaves are used in potpourri and act as an insect repellant.

Growing Coleonema album

Pot specimenColeonema album can be used as an accent plant in the garden, a hedge plant or as a filler plant in a mixed fynbos bed with companion plants such as Erica, Restio, Protea, buchu, herbaceous perennials such as Geranium incanum, Felicia aethiopica, Scabiosa incisa, and shrubs such as Salvia species, Metalasia muricata, Euryops virgineus. It is also an ideal container plant for a sunny position on a stoep or patio.

This species requires full sun and soil that is acid, well drained and composted. Add a layer of mulch to keep the soil and roots cool in summer, retain soil moisture and reduce weeds. Buchus are best planted out during the winter-spring season. Plants require good watering in winter and moderate watering in summer. Do not allow plants to dry out. Once established in your garden they will survive long periods of drought.

Coleonema album is easily grown from seed. Fresh seed is collected from the previous year's flowers and stored in brown paper bags upon ripening. The optimum time for sowing is during autumn. Seed are cleaned and sown on a prepared medium of sand and compost in equal parts in a seed tray. Cover seed with a thin layer of bark and water. Place seed trays in a covered area with good light and ventilation. Keep seed trays damp and germination will take place within 1 to 2 months. Seedlings are pricked out when 4 true leaves have developed. The growing tips of seedlings are pinched out to encourage bushy growth. Feed buchus regularly with a balanced nutrient

Cuttings have the advantage of producing a larger flowering plant quicker than seedlings. Tip cuttings, 50-70 mm, are taken from the current year's growth from August to October. Prepare cuttings by making a clean cut below the node and remove a third of the foliage. Dip the base of the cutting in a rooting hormone. Firmly place the cuttings in a medium of 50 % bark and 50 % polystyrene. Ideally these cuttings should now be placed in a well-aerated propagation unit with a bottom heat of 24°C. Rooting occurs in 9 to 11 weeks. Carefully pot the rooted cuttings using a well-drained humus riched fynbos-potting medium (2 parts leafmould, 1 part coarse sand). Plants will be ready for planting in 7 to 8 months. Feed regularly with a well-balanced nutrient. Yellow leaves can be treated with an application of iron chelate.

Coleonema calycinum


Coleonema album vs Coleonema calycinum.
These two species can easily be confused. C. calycinum grows to a height of over 2 m and also bears white flowers from September to October. It occurs naturally on mountain slopes near Worcester and from Caledon to Bredasdorp (limestone hills).

Coleonema album

Coleonema album may be distinguished from all other species by having:

  • Staminode mostly connate with the petal
  • Flowers white, 6-7 mm diameter
  • Leaves 12-13,5 mm long. The presence of a small conelike gall, found only in this species, is a useful character for identification.
  • Grows to a height of 2m.
  • Sweet-scented

Coleonema calycinum

Coleonema calycinum identified by the following:

  • Leaves 13-19mm long, 0,7-1mm broad
  • Calyx lobes 1,2mm long
  • Flowers 5,5-6,5mm diameter, flower buds are pink, flowers white when open.
  • Grows to a height of over 2m.
  • Petals obtuse (rounded or blunt) and staminode connate (having similar parts joined by growth) with petal in the lower half.
  • Rum-scented

References

  • MASON, H. 1972. Western Cape Sandveld Flowers. Struik Publishers, Cape Town.
  • LEVYNS. M.R. 1966. Guide to the flora of Cape Peninsula. Juta and Company, Limited, Wynberg.
  • GOLD, M. 1992. The Buchus Cultivation and Propagation. National Botanical Institute, Kirstenbosch
  • 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, Missouri.


Norma Jodamus
Horticulturist, Kirstenbosch National Botanical Garden
September 2003



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