Zantedeschia hardiness
John Grimshaw (Tue, 16 Jun 2009 10:33:30 PDT)

Jim McKenney wrote:

This issue has been touched on but I think not yet fully explored.
Zantedeschia aethiopica has a wide range in South Africa, encompassing both
winter and summer rainfall areas.

It seems sensible to me to assume that most importations of Zantedeschia
aethiopica have been from the area around Cape Town, where it is very
common, even growing at the very tip of Cape Point. These winter growers
would certainly be tender in northern Europe, necessitating the glasshouse
culture/underwater techniques to survive.

I have collected seed of Z. aethiopica on the Sani Pass, in Kwa-Zulu-Natal,
a classic summer-rainfall location and source of many hardy plants for UK
gardens. The seedlings are absolutely hardy here and flower in midsummer.

Mulling over it, I came to the thought some time ago, that the generally
reliably hardy clones in the UK, e.g. the old but unspecial 'Crowborough'
and the recently named 'Glencoe', are probably from the summer-rainfall
area, though this is impossible to prove. If so, it demonstrates the
importance of provenance when selecting South African material for garden
use. (Another plant with similarly wide distribution in SA & reputation for
tenderness is Melianthus major: again, one suspects that most seed has come
from the Western Cape, and one wonders how material from the Drakensberg
would fare.)

The pink-throated form of Z. aethiopica also seems to be entirely hardy
here, and occurs in eastern south Africa somewhere as a wild plant.

Z. albomaculata survives outside here, but is late to emerge, and does not
flower very freely.

John Grimshaw

All messages in my Inbox received between September 2008 and 30 May 2009
have been deleted: please resend anything you feel is important!

Dr. John M. Grimshaw
Sycamore Cottage
Colesbourne
Cheltenham
Gloucestershire
GL53 9NP

Tel. 01242 870567