Amorphophallus in Ohio?

Steve Marak
Sat, 17 Jul 2010 21:34:23 PDT
Hi Diane,

Amorphophallus konjac (now the accepted name for A. rivieri) is by far the 
hardiest of the genus, and with a little luck will overwinter outdoors as 
far north as zone 5. I've had it outdoors in NW Arkansas (nominally zone 
6) for about 25 years, and plants I've given to people in Denver have also 
survived for years now. Not every clone is that hardy, though - it just 
happened that the first clone I got was. I'm collecting every clone I can 
to test outdoors, but don't have any worthwhile information yet except on 
that first one.

As to the spreading, there are a couple of possibilities. While konjac can 
set seed, it's rare unless you have more than one clone, and I assume 
they'd know if that was happening. The seed heads are typical for aroids, 
and obvious, very like Arum italicum.

It also has several modes of vegetative propagation. It does produce 
offsets, and in many clones once a tuber reaches a certain size, usually 
the year it's large enough to flower, it will "split" into 4 or 5 smaller 
tubers. Some clones also produce stolons with offsets at the end. But I've 
never seen a stolon more than maybe 15 inches (40 cm or so) long.

If the new plants are showing up more than a few feet from the parent, 
I'd have to think something else was moving small offsets.


On Sat, 17 Jul 2010, Diane Whitehead wrote:

> I received a request for information that has intrigued me.  I am not 
> able to answer, but perhaps one of you has an idea.  I didn't think 
> Amorphophallus would stand the winter in Ohio.  Isn't it semi-tropical?
> Here is the query:
> About 15 years ago we received 1 bulb of the Amorphohallus rivieri. At 
> last count we have 75 plants growing around our property. These 75 have 
> not been planted or in any way encouraged. They just sprout where ever 
> they choose and surprise us in out of the way locations far from 
> anyother clumps. If they are a bulb, how are they spreading? In all 
> these years we have only had one plant produce seed. Each spring there 
> will be only one or two that bloom, for which I am very thankful!! I 
> have done internet searches and am unable to find an answer to the 
> abundant proliferation of this unique plant on our property. We live in 
> Cincinnati, OH.

-- Steve Marak

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