Bulbs for Continental climates, Upper Midwest--TOW

Steve Marak samarak@arachne.uark.edu
Sat, 26 Apr 2003 22:15:39 PDT
Miscellaneous comments on Jim Shields interesting post ...

On Mon, 21 Apr 2003, J.E. Shields wrote:

> Claytonia virginica is naturalizing here, as it is a native. ...
> I'd be interested in how the other species of Claytonia are doing for
> folks in their gardens.

C. virginica is native here (NW Arkansas, USDA zone 6, but overnight temps
as low as -20 F/-26 C) too, and I love it - I think it's underrated and
underused. There are places where it grows by the thousands in people's
lawns, some of whom devote much time and effort to killing it. I'd love to
have that problem.

Sometimes I can get in ahead of construction (usually chickenhouse
construction; Arkansas has way more chickens than people) and rescue some
things, and I've collected some nice forms. I think the best compare
favorably with any small bulb. I haven't tried other species but would
love to do so.

> Zantedeschia is one that we need to explore further for hardiness. ...
> I've heard of and have received a few tubers of Zantedeschia cultivars
> that survive in the ground in zone 7 and seemingly even in USDA cold
> zone 6.

I have a number that have survived my zone 6 winters for at least 10 years
now, and I'm acquiring some of the new hybrids and putting them out, too.
I was surprised to find that Z. aethiopica, the large white one, normally
considered the most cold hardy, does NOT do well here. Temperatures
fluctuate wildly here in winter and spring, and every year it starts
growth too early and gets badly frosted; they tend to decline over several
years and eventually disappear.

The pink Z. rehmannii and yellow Z. "elliotiana" types (one of the aroid
taxonomists chides me if I call it a species) do very well, as do the
hybrids I've tried thus far. They get no snow cover, no mulch, no
coddling, and not much supplemental summer water (summer is our dry
period, with up to 12 weeks of no rain in a bad year), but flower well and
set seed. As an aroid lover, I'm quite pleased by this. (Planting depth -
I just stick them in the ground, since they'll find their own preferred
depth. That seems to be just a few inches down.)

There are several other "tropical" aroids of surprising hardiness -
Amorphophallus konjac is a long-term outdoor survivor here, as is
Sauromatum venosum. Clumps of Dracunculus vulgaris can be found here and
there in old gardens, surviving more or less on their own for decades
(more than 70 years, in one instance).


-- Steve Marak
-- samarak@arachne.uark.edu

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