Maximum minimum temperatures for Arisaema

[George R Stilwell, Jr.]

Paul,

There has been some discussion of required low temperature for Arisaema,
but much of it
is not in the archives. As I understand it, we simply don't know the
maximum minimum temperature
and period for Arisaema especially by species.

What we do know is that 40F (4.5C), refrigerator temperature, for 2
months is adequate for almost
all species. We know that one month will sometimes work for A. sikokianum
and that 3 months
often works even better.

Unfortunately, there's no experience reported at other temperatures. Some
of us suspect that
50F (10C) may be cold enough particularly if held for 3 months, but this
is speculation, not fact.

We have reason to believe the plants do not simply die if kept warm.
Rather they gradually
decline in vigor, stop blooming, and ultimately do die. There are a few
Florida growers who
can attest to this behavior.

Currently, there are a couple of AEG members who are trying the
"dig-and-refrigerate"
regimen. Sort of like northerners (southerners, down under) dig tender
bulbs and store them
to prevent frost damage. No reports of the results so far.

Much of our experience comes from forcing seedling tubers to put forth 3
years growth per
year by refrigerating and regrowing cyclically. This is not exactly
parallel to treating mature
tubers as you can appreciate. But it does give some clues. Experience
with mature tubers
grown in some warm climates indicates the decline in vigor is real.

Ray
GRSJr at Juno.com

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