Calostemma purpureum
Robert Hamilton (Sun, 05 Oct 2003 04:12:15 PDT)

Hi Jane,

Calostemma grow as a summer dormant plant for me - even though we
get summer rainfall it is usually not heavy and persistent
enough to have any great effect on the garden or the potting mix
of exposed bulbs.

After reading your posting I have revisited an article by Robert
Gibson in an Australian Native Plants publication and thought it
would be of interest to quote his thoughts on cultivation.

"Calostemma purpureum is an easy plant to cultivate and propogate.It
grows easily in standard potting mix in a full-length plastic pot at
least 15cm accross, and grows in most garden soils. Given their bulbous
nature they respond readily to changes in soil moisture levels. In
dry conditions the plants become completely dormant and all above
ground growth dies away. The bulbs readily produce new growth when the
soil becomes moist, with a flush of new leaves and, periodically,
flowers triggered by at least some periodic heavy watering. Leaves
will survive for several months provided the soil or potting mix
remains moist.
They occur naturally in areas that receive light winter frosts, which
they usually survive, however, this species is probably best thought
of as a summer growing bulb. "

They survive frost here to -2C and I am sure much colder in
Canberra where Paul Tyerman grows them and reported some interesting
colour varieties from Canberra Botanical Garden where they would be
on a summer dormant cycle. The images of these colour varieties
are on the wiki.

Jim Lycos grows them in Sydney where the rainfall pattern is
different so may tell us how they grow there.

Jane, it sounds as though it may be worth drying off your plants
for winter to see whether spring / summer watering stimulates
flowering.

Cheers,

Rob in Tasmania
Zone 9 equivalent.