[NAFEX] Cold Hardiness in Peaches
mauch1 at aol.com
mauch1 at aol.com
Tue Jan 3 11:27:23 EST 2006
First - For some of the Flamin'Fury and Stellar series Check out Adams County Nursery,
though mainly commercially oriented, they do sell retail (mailorder) to homeowners.
Nice company. Will not send peaches for fall planting. I do not believe they
have P24C (P24-007 they have, but it appears to be different). You might want
to call them as sometimes their web pages do not reflect their exact inventory.
(After attending NAFEX conference in New Hampshire, wanted the Hampshire apple -
they had it but did not list it completely (was in price list, but not in descriptive
<<Why did most of the apricot flower buds and almost all of the peach
flower buds die after only -23 F min last year - even on the -40 varieties
- when they went through -29 F the winter before with little or no damage?
My guess is that it had something to do with a persistent period of cold
(but not severe) weather without snow cover in December that produced deep
frost. In checking this with two other fruit breeders with an overriding
interest in cold hardiness, neither thought that this should make any
difference to flower bud mortality. But even if the conditions that
produced the deep frost didn't directly cause the buds to die, I'm not
ready to agree that it had no influence on the hardiness system in some
indirect way, even though I couldn't begin to say how. To me it is more of
a mystery that some trees are not damaged by extreme cold than it is that
some are damaged. You don't have to stand out in the orchard in -40 weather
for long to appreciate what they have to be able to endure and the complex
system of changes that allows them to do so. >>
Dave, I live in balmy zone 6, but have decided to be insane enough to try to
grow apricots. I suspect that you lost the buds not to the -23, but to fluctating
temperatures nearer spring:
<< Why weren't the vegetative buds and branch tips on my peaches and
apricots also killed? Why didn't my tender plums and pears have any flower
bud damage whatsoever under these same conditions? Because they are somehow
Also, prunus as a genus, usually has its flower buds open before its vegetative
buds, so they will often survive while the flower buds are damaged/killed. I believe
that each species has a different relative hardiness, and a timing for when they tend
to come out.
Also as an aside, I was at a presentation on grapes and cold hardiness. It is generally
known that vinifera (wine grapes) are not as hardy as lambrusca (Concord). What was
surprising was at the depth of dormancy vinifera can take almost as cold a temperature
as Concord*. However as temperatures warmed and fluctuated towards spring, the
vinifera were far quicker to shed their dormancy and slower to return to dormancy. So
at a certain point they were far less hardy that the Concord because they were no longer
as dormant. Which makes sense as vinifera are from a mediterranean climate, which is
affected by maritime temperatures and fluctuate less than temperatures on a more
continental east coast.
* (the testing was done using exothermic detection (as water freezes it releases
a spike of warmth to settle into its new state (ice). Grapes put under these tests had
two spikes (one when the water between cells froze) and then another when the water
in the cells froze (bud kill).
SE PA, zone 6
40° 5' N 75° 51'W
~650 ft elevation
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