Due to social distancing measures and the need to maintain public safety, we are cancelling the Grape Pruning workshop that was to be held at the UVM Horticulture Research & Education Center on March 21.
Here are some good pruning resources that may help guide you in pruning your vineyard:
· Finger Lakes Grape Program (FLGP): How to Prune Grapevines
· Michigan State University Pruning and Training Top Wire Cordon Vines
It’s not a bad idea to assess winter bud damage on a few vines and adjust your pruning if appropriate. A visual assessment is easy to conduct. We encourage growers to collect their own primary bud mortality data prior to pruning, if possible. The procedure is fairly quick and requires no special equipment besides a hand lens or magnifying viewer. A helpful video from the Cornell Cooperative Extension Finger Lakes Grape Program that outlines the process may be found at: https://www.youtube.com/watch?v=_RHJ5mY3fAs .
Dr Jim Meyers offered me the following model output that compares observed temperatures against expected bud hardiness on multiple cultivars for our farm in South Burlington, VT. The bad news is there were a few days in February where some damage may have occurred on cold-hardy cultivars, with Marquette (green line) potentially having been damaged on three days this winter. The good news is that grapevines have a remarkable system for ensuring their growth and potential cropping through their compound buds, and that generally grapevines can sustain 30% or more primary bud death before we get too concerned. You may also see that, in the model, Concord was not damaged by temperatures seen this winter. There is a range of bud hardiness among the commonly-grown cultivars in Vermont and the surrounding region, and I don’t see a lot to worry about in this table.
Good luck pruning out there, and let me know if I can help with anything.