Leo A. Martin leo@possi.org
Sun, 14 Apr 2013 13:48:45 PDT
> I know in the summer they go dormant. Would I just entirely skip watering
> during this time? If they were planted in the ground; they wouldn?t dry
> out (I think), so perhaps a light misting directly over the tuber once
> a month during this time would be ok?

A few Aprils ago I saw Lewisia rediviva blooming abundantly in eastern Washington State.
It has many, large flowers for such a small plant and generates a very large amount of
seed. It grows there on top of flat ancient lava flows, nestled into cracks. There were
1-5 plants per square meter. We were also there to see Pediocactus simpsonii, which was
also abundant.

Locals told me a little rain could fall in late autumn when it was already quite cool,
and a little snow might occur during the winter. Spring and summer are dry. Summer
daytime temperatures there are frequently well over 100 F / 38C, and there is very
little vegetation other than some wispy clumps of grass on the black lava, which must
get extremely hot in summer. Winter lows can be below zero F / -15C for extended periods
of time. The terrain surrounding the lava flows is short grassland, suggesting low
overall rainfall.

This would suggest to me the plant makes a rapid growth and flowering push during spring
runoff, and is also able to absorb water in late autumn when not active above ground. I
don't know how much moisture remains below the lava surface during the long summer but I
would guess not much.

Most things in Portulacaceae are extremely tolerant of drought. I can't grow Lewisia
here in Phoenix due to the heat, but its relatives here generally die of overheating,
not drought.

If you like Lewisia and you like miniature plants you should look into some of the
southern African members of Portulacaceae in genera Anacampseros and Avonia. Most are
summer growers and many have tubers underground. Mature plants will mostly fit into a 1"
pot and they are very easy from seed, usually flowering within a year. Their seed is
rarely viable beyond one year. In addition there is one species in Australia and are
several in Mexico of a tuberous portulacaceous genus again called Grahamia after some
confusing years of anomie.

Leo Martin
Phoenix Arizona USA

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