Lewisia
Jane McGary (Sat, 13 Apr 2013 09:21:17 PDT)

Lisa may be mixing up the two sorts of Lewisia species, the evergreen
and the deciduous.

At 05:09 AM 4/13/2013, you wrote:

The commonly grown L. cotyledon and L. tweedyi (which has been under
discussion) are evergreen. Tweedyi goes semi-dormant in winter. Some
species, such as L. brachycalyx, L. nevadensis, and L. oppositifolia,
are summer-dormant. They do not have "tubers." The storage organ is
an enlarged, partly underground stem known as a caudex. In many but
not all species, these caudexes (or caudices) multiply as the plant
ages, and it can be lifted and propagated by division.

I have always grown the deciduous species with my summer-dry bulbs,
under cover, but I planted some L. nevadensis seedlings on the rock
garden a couple of years ago, and they are flowering this spring.

Evergreen species in the Pacific Northwest should be planted where
there is extremely good drainage, such as in a pocket of a dry stone
wall. Some people have good success with L. tweedyi west of the
mountains (it is native east of the Cascades, in a much drier area)
by planting it within the drip line of a large conifer.

Jane McGary
Portland, Oregon, USA