Watsonia hysterantha

J.W.Mathews & L.Bolus
Family: Iridaceae
Common names: suikerkan, herfskanolpypie, rooipypie (Afr.)
Conservation status: Rare

Watsonia hysterantha.Photo: G DuncanWatsonia hysterantha is one of numerous, bright, dwarf watsonias endemic to Western Cape. While several tall-growing watsonias are frequently used in roadside plantings in South Africa, the potential of dwarf species as rock garden subjects has yet to be fully appreciated by a wider audience.

Description
W. hysterantha is a most striking scarlet-flowered, autumn- and early winter-blooming species up to 600 mm high with narrow, erect, leathery leaves. It is one of the larger dwarf watsonias and is unique within the genus in being the only member that produces its flowers before the leaves have fully developed. Its storage organ is a subterranean corm, covered with several layers of tough outer tunicsis and it is a strictly winter-growing plant, sending up its flower spikes just before, or directly after the first autumn rains, followed shortly afterwards by the leaves that persist until late spring and die off in early summer. Towards the end of spring, the large, attractive seed capsules split open, allowing the light, winged seeds to be effectively dispersed by wind.

Derivation of name and historical facts
The genus Watsonia commemorates the eighteenth century English physician Sir William Watson. The specific epithet hysterantha is derived from the Greek hyster, meaning after, and anthos, the flower, and aptly refers to the appearance of the leaves after flowering has taken place. W. hysterantha is a relatively recent discovery, collected for the first time in the 1920s by Mr J.W. Mathews, first Curator of Kirstenbosch Botanical Garden, who found specimens near Langebaan. It was formally described in 1927 by Mathews and Dr Louisa Bolus, a former Curator of the Bolus Herbarium at the University of Cape Town.

Watsonia comprises 51 species and is endemic to three southern African countries, South Africa, Lesotho and Swaziland, with the greatest diversity in the southwestern Cape.

Growing in habitat: Photo Copyright Graham DuncanDistribution and habitat
W. hysterantha has a very limited distribution along the Cape west coast where its corms are confined to deep cracks of granite outcrops that provide effective protection from ravenous moles and porcupines, often forming very thick clumps. Its conservation status is currently categorized as Rare and in certain parts, its habitat has been destroyed or severely degraded due to the development of holiday homes. Fortunately though, a portion of its range falls within the boundaries of the West Coast National Park, as well as in a couple of private nature reserves near Darling.

Ecology/Pollination biology
Like several other scarlet-flowered Watsonia species with long, narrow perianth tubes, W. hysterantha is probably pollinated by sunbirds that feed on the plentiful sugary nectar held at the base of the perianth tubes, hence the beautifully descriptive Afrikaans common name suikerkan, that translates literally to sugar can.

Growing Watsonia hysterantha

W. hysterantha is seldom grown but is admirably suited to rock garden pockets in temperate climates, where the corms can be allowed to remain undisturbed for several years. It requires a full sun position and a sharply drained, preferably acid soil, containing well-decomposed compost, and needs regular watering during the winter growing period. The corms multiply prolifically by offset formation and thick clumps should be lifted every three years to maintain good flowering performance, as excessively thick clumps seldom produce flowers. During the summer dormant period the soil must be kept dry, as the corms soon rot under constantly moist conditions. This species is thus not suited to general garden cultivation but rather to a sunny rockery in a corner of the garden reserved for winter-growing Cape bulbs. Due to its vigorous root system, W. hysterantha is not ideally suited to containers except if they are very large (i.e. having a diameter of 35 cm or more).

Thick clumps can be lifted and the offsets separated at any time during the summer dormant period. They should preferably be replanted as soon as possible thereafter into dry soil, as corms kept in packets often fall prey to mealy bug infestation when stored for extended periods. In addition to offset formation, W. hysterantha is easily propagated by seeds sown in deep seed trays or seed beds in autumn, in a well-drained, sandy medium containing some finely sifted, acid compost. Sow the seeds thinly to prevent overcrowding and minimize the occurrence of damping-off and rust fungi, and cover with a 3-5 mm layer of sowing medium (seeds sown too shallow tend to float to the surface after watering, and fail to germinate). Water well using a fine rose spray and keep moist. Fresh seeds germinate within three to four weeks, and at the beginning of the second season, young corms can be planted out into bags and be grown on for a year or two. Under ideal conditions, flowers can be expected for the first time during the third or fourth season.Unlike most other Watsonia species, the foliage of W. hysterantha is hardly ever subject to attack by unsightly rust fungi.

References

  • Duncan, G.D. 1989. West Coast splendour. Caltex Oil, South Africa.
  • Duncan, G.D. 2002. Dwarf watsonias. Veld & Flora 88: 94-98.
  • Goldblatt, P. 1989. The genus Watsonia. Annals of Kirstenbosch Botanic Gardens 19: 133, 134.
  • Jeppe, B.J. & Duncan,G.D. 1989. Spring and winter flowering bulbs of the Cape. Oxford University Press, Cape Town.

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Author
Graham Duncan
Kirstenbosch Botanical Gardens
January 2004

 


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