contractile roots, rot

[McClements, Jim]

AEG'rs

On 8-29 Louise Parsons asked:

>My question is twofold:  Do arisaema have
>contractile roots which would pull them naturally deeper in the ground over
>time and is my observation correct that larger, more mature, tubers are less
prone >to rot ?

There's no question in my mind that young arisaemas being grown in pots pull
themselves deeper. Whether this continues with older tubers, I don't know.
>From the description by some of the recent China explorers of how deep some
tubers are in the wild, it sounds as if it does. The only fly in the ointment
is that arisaema roots seem to be "annual", at least in young plants, whereas
I always envision contractile roots as being sturdier, older structures.

The question about rotting is one of those chicken and egg things. I think
that it's probably right that after an arisaema has been established in the
garden for a few years it's less prone to rot. But this may be more because
it's happy in its environment, rather than a function of size or age. The
opposite may be true for freshly purchased tubers. My experience is that the
large ones are MORE prone to rot than the small ones, which is undoubtedly
due to their being injured during the collection and transporting process.

I'd certainly like to hear some other input on this.

Jim McClements