Lewisia
Jane McGary (Mon, 26 Jan 2004 10:33:20 PST)

A good source for information on cultivating lewisias is B. LeRoy Davidson,
"Lewisias," Timber Press, 2000. Davidson wrote from the perspective of the
Pacific Northwest of North America, but he was in contact with many growers
in the UK and eastern North America and mentions their experiences with the
genus.

An important point Davidson makes is that almost all lewisias need plenty
of water in their growing season. Those that live in regions with very arid
summers typically inhabit seeps, snowmelt areas, and deep screes where the
substrate remains moist a long time. They are, however, quite susceptible
to bacterial and fungal diseases, which is probably what carries them off
east of the Rocky Mountains and in other areas with hot, humid summers.

The species Lewisia columbiana seems to be the most successful in damp
climates, particularly its showy subsp. rupicola. There are a number of
hybrids from this species.

A good selection of evergreen lewisias can be obtained from Mt. Tahoma Nursery:
<http://www.backyardgardener.com/mttahoma/>

Deciduous species are easily grown from seed. They hybridize freely in
cultivation, so wild-collected seed is safest if you want taxonomic purity
(not guaranteed, however; there are hybrid populations in the wild). I grow
these in the bulb frame along with western American bulbs and enjoy them a
lot in the spring.

Jane McGary
Northwestern Oregon