[NAFEX] Ultra hardy sweet cherry rootstock
bnikolai at shaw.ca
Wed Jun 11 23:10:14 EDT 2003
I just returned from a week in Alaska, specifically Anchorage and Fairbanks.
While in Anchorage, fellow Nafexers took me on a tour of a few orchards, and
I was stunned to see sweet cherries, obviously several years old, with a
good crop of cherries that had just set! The varieties were Kristin, Sam, a
Bing seedling, and another seedling called Clarke. I think there was also a
tree of Lapins. Apparently near the ocean in Anchorage, the real zone is
zone 5, not zone 3 as the maps say. Minimum temperatures at orchards near
the ocean are only -15 to -20F, warm enough to allow sweet cherries to
survive the winter. However, only a half hour away inland, it is zone 3,
with minimum temperatures often approaching -40F in winter. The sweets
ripen mid Sept. there, much later than other areas, due to the cool summers.
65 to 70F is a hot day there.
One of the growers of the sweet cherries had experimented with every prunus
species he could find for a rootstock. Nothing worked as sweet cherries are
touchy re rootstocks, except for Amur cherry, prunus maackii. This is a
beautiful tree, common here and hardy here in Edmonton, zone 3, with bright
copper coloured bark that seems to peel like a birch. I saw several trees
that were obviously grafted many years ago on Amur cherry, about 2 ft. above
the ground level. I don't know why they weren't grafted at ground level,
but they weren't. The grafts had healed in very nicely, and were neither
over or under growing the rootstock. It was quite interesting to see the
copper bark suddenly turn to cherry trunk where the graft union was. The
trees seemed quite productive.
Has anyone else tried Prunus Maackii, Amur Cherry, for sweet cherry
rootstock? The trick was to graft the Amur cherry right at green tip. It
didn't seem to work if you grafted either earlier or later, so they said.
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