Watsonia hysterantha

Watsonia hysterantha Mathews & L.Bolus is endemic to granite outcrops on a small section of the western Cape coast, South Africa.

It is winter growing and summer dormant like many other South African irids, but unusual in flowering in autumn at the beginning of the growing season. This not hysteranthy in the strict sense of producing pre-formed flowers direct from a bulb before the leaves like Amaryllis and Nerine. Instead, corms that have reached a critical size in the previous year “bolt” when they start growth, producing a flowering stem with about 4 short sheathing leaves. Smaller corms produce a vegetative shoot with about 6 leaves to 70 cm long and no stem above the ground.. As in all the watsonias, growth is sympodial – meaning that growth is terminated by the inflorescence. Each corm therefore dies after flowering, but not before producing offsets below ground as well as seed.

A practical consequence in a warm autumn like we had in Adelaide this year is that, while the hysteranthous amaryllids were all late in coming into leaf and many missed flowering this year, Watsonia hysterantha did not wait for low soil temperatures but started growth in early March as normal.

Per the Royal Horticultural Society colour charts, the flower colour is RHS 40B; it’s quite literally miniate, or the colour of red lead oxide.

This watsonia can be grown in the open garden but to keep track of the corms I grow it in 300 cm pots, lifting and dividing each summer. It multiplies vegetatively, and the only difficulty I have found with its management is in maintaining a high proportion of flowering-size corms. My stock came from Bruce Knight of Sydney, who imported seed in about 1995. As it is endangered in its natural habitat and further importations may no longer be possible, it’s important that existing stocks in Australia are maintained. Another Watsonia species, W. humilis, is even more critically endangered but at least one strain of it has been passed between gardeners in this country since its importation in the 1830s.

Reference

Goldblatt, P. (1989) The genus Watsonia. (National Botanic Gardens: Kirstenbosch) ISBN 062012517

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