winter hardiness

Tony Avent
Sun, 27 Jun 2004 09:31:16 PDT

	Great point.  The rate at which speciation occurs certainly affects the
loss of winter hardiness in many plants moved around by nature.  T.
underwoodii could simply be speciating faster than T. lancifolium and
therefore loosing it's original hardiness faster.  Fred Case also says that
that T. underwoodii is the one of the only southern trillium species that
causes problems for him in zone 4b for the reason you mention.  Another
plant from the same area which shows the opposite trait is Baptisia
simplicifolia.  Even in the Florida Panhandle, it doesn't emerge until
June.  The emergence date stays virtually the same when it is grown in zone
5.  That trait certainly isn't typical for a plant "originally" native to

At 12:22 PM 6/27/2004 -0400, you wrote:
>Tony A wrote "Most plants in the Florida panhandle have hardiness to at
>least zone 6 and some further north.  Originally, many of these plants
>resided in the Ohio or Delaware Valleys and were relocated during the last
>ice age.  They never bothered to lose their winter hardiness."
>But some of them did adapt to their new deep south environment such they no
>longer are effectively 'hardy' in zone 6 even though their rhizomes may not
>be killed directly.  Trillium underwoodii from around Chattahoochee and
>Trillium decipiens from a little further north in Georgia are perfect
>examples.  Their rhizomes are indeed 'hardy' but they have adapted to the
>deep south winters and they put up leaves as early as December here in Exton
>(zone 6b/7), pretty much irrespective of local climatic conditions.  They
>seem to respond to a calendar - and of course here this new top growth is
>rapidly trashed by temperatures below about 15F.  A couple of years of this
>and they are no more.  It is interesting to note that Trillium lancifolium,
>which grows in the same woods as T. underwoodii near Chattahoochee, has
>learnt to keeps its head down longer, and so fares better here without
>pbs mailing list
Tony Avent
Plant Delights Nursery @
Juniper Level Botanic Garden
9241 Sauls Road
Raleigh, NC  27603  USA
Minimum Winter Temps 0-5 F
Maximum Summer Temps 95-105F
USDA Hardiness Zone 7b
phone 919 772-4794
fax  919 772-4752
"I consider every plant hardy until I have killed it least
three times" - Avent

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