Pinellia cordata
Mon, 30 Oct 2006 09:20:19 PST
On 30 Oct 06, at 10:31, Jim McKenney wrote:

> Alberto Castillo wrote " Not only that, forms of P. cordata have
> foliage that is among the most attractive of all...Superb."
> Yes, it certainly is. But in my experience it is as difficult to
> please as the other members of the genus are easy. 
> I've tried to grow it as a garden plant, and while it persists for
> several years, it grows only haltingly, does not increase and
> eventually disappears.
> The site where I've tried it is very shady, and my plants grew in the
> company of other woodland plants such as Asarum, Podophyllum, Trillium
> and various ferns. 
> Does anyone who grows this plant well have any suggestions for my next
> trial?

I'm surprised it doesn't do well with you. A great many Japanese 
plants that do well in the east are miserable failures on the Pacific 
Slope: if they don't desiccate to nothing during the dry summer, they 
rot away during winter rains.

The rot problem may not be as bad in well-drained locations, but I 
live in a former swamp and it's a quagmire all winter long.

Failures: Tricyrtis; Podophyllum emodi; Uvularia; Pinellia cordata 
(and some other species, too!); and many others.

My first try at Pinellia cordata behaved like yours: it dwindled away 
and was gone in three years or so.

By the time I'd gotten new samples, I'd learned a thing or two, so I 
potted them up and to this day grow Pinellia cordata solely in a pot. 
They are kept in shade and watered plentifully during the summer, but 
allowed to go bone dry during the winter. (Because our winters are so 
wet, the relative humidity is high and even left unwatered, my pots 
of P.c. don't actually desiccate.

I've had them the better part of ten years now and they're still 
going strong.

I use a fairly open mix with lots of pumice in it. Perhaps a lot of 
these woodlanders are native to wooded sites where the annual leaf 
fall means the top layer of soil is always quite airy; in a pot, the 
soil usually compresses with time and becomes pretty airless.

Pumice opens the soil up and keeps it airy more or less permanently.

I am careful to sow all the bulbets formed, both those in the leaf 
axils and those at the base of the leaf stems.

Pinellia cordata emerges quite late in the spring, and bulblets don't 
"germinate" until even later when the weather warms up. [All things 
are relative: "warms up" means it reaches daytime temps of 65-70F.]

Anent Alberto's remark about the beautiful markings of the leaves: 
there is a form of Pinellia cordata with plain green leaves. At least 
that's what it's called. I started with a single leaf and its two 
bulblets and have gradually built up a small population in one pot.

Question: does anyone know the features that distinguish "Don Jacob's 
Form" from "Roy Herold's Form"? One seems to have slightly larger 
leaves and they don't emerge at exactly the same time in the spring, 
but surely there's some more obvious difference.

Rodger Whitlock
Victoria, British Columbia, Canada
Maritime Zone 8, a cool Mediterranean climate

on beautiful Vancouver Island

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