The Ides of May

Michael Mace
Mon, 16 May 2011 11:59:03 PDT
Max wrote:

>>I blame low winter rain (we've had about 20" per year, or less, until this
year), but it could also be compete desiccation in the summer. I welcome any

I haven't tried either of those in beds rather than pots, so take this with
a grain of salt, but here's my vote:  Summer dryness is killing the I.
viridiflora.  I've heard from several growers that it does well with a bit
of summer moisture.  According to Kirstenbosch, it grows in mountain slopes
near Tulbagh (  If you
look at the South African climate map on the wiki
gif), that area averages about two fully dry months in the summer, and even
in summer it can get about half an inch of rain per month.  That is very
different from the part of California that you and I inhabit, where a five
month complete summer drought is normal.  Tulbagh's summer rain pattern is
similar to Eureka, California.

However, I bet something else is making your D. ida-maia suffer.  I grew
them in pots for years with total summer dryness, and they were very happy
-- making offsets, seeds, etc.  But they tended to dive to the bottom of the
pot, and would then die in a couple of years if not repotted.  I forgot to
do the repotting at one point, and that was the end of my Dichelostemmas. I
have been trying to find seeds to get them started again.  They sure are

>>I'd be interested to hear of other floriferous Calochortus.

Okay.  This is a *very* early report, and I'm not ready to draw any
conclusions, but this year I switched some of my bulbs from standard 8-inch
(20 cm) plastic pots to Strewe Treepots that are 8" wide and about 16" (40
cm) deep.  They look like designer wastebaskets.  I put a few of my
Calochortus in them, because like Dichelostemma they tend to dive deep in
normal pots and then die.

The result so far is some very robust, happy-looking Calochortus plants.  C.
uniflorus bloomed for several months, and three different Mariposa species
are just now coming into bloom.  It's too early to judge, but I think deep
pots really do help.  That fits with the advice I've gotten from a couple of
veteran growers.

San Jose, CA (min temp 20F / -6C)

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