persimmon winter damage '13 - '14
Tallying up the damage to my persimmon trees over the past winter. Have waited to this point since some of the trees have been very slow to bud out, but I think that the call can be made on all of them at this time. The past winter here as in many other places was unusually cold but the real damaging event was the night in January when temps fell to -11 or -12F. There was no significant snow cover here.
The trees that I protected that night with tarps and heat sources sustained enough damage that they will not fruit this year, but the size of and the prospects for the trees remain unchanged.
Trees on lotus rootstock, which suffered severe dieback, all were lost.
Unprotected trees on virginiana rootstock either sustained severe dieback or died back to the rootstock. Varieties surviving with severe dieback were 20th century, Fuyu, Honan Red, Giombo, Smith's Best, Tecumseh, Nikita's Gift, Eureka. Unprotected varieties on virginiana not surviving were Hana Fuyu, Ichi ki kei jiro, Korean, Saijo, Tam Kam and Maekawa Jiro .
Most trees with severe dieback have had robust recovery, some with 6 feet of growth, 3 foot laterals and 1 foot sublaterals, but some have first budded as late as July 1 and so have had only modest regrowth to this point.
The hybrid Rosseyanka showed no dieback and is cropping normally. I lost one mature grafted virginiana, NC10. I have never heard that this one was less cold hardy than the others, and while I doubt that it is, I will replace it with a different early variety.
My biggest and really only major loss was severe dieback to a mature 20th Century that will take about 5 years to recover.
A few things that I draw from this is that in zone 6 (I also have a persimmon orchard in zone 7 which had mild dieback and poor cropping but no significant damage to any of the trees) I will keep my kakis to 8 or 9 feet height and have a tarp, wire and heat source ready if needed for each tree at risk, to be used if temps are forecasted to drop below -7F. I will graft low, not only to keep down the total height of the tree, but I found that in the event that there is severe dieback, those trees grafted lower are more likely to survive. Immediate regrowth can save up to 2 years in waiting to restore the tree compared to regrafting the rootstock.