1 - Early fall pruning a Concord grape vine, while not recommended, will probably not kill the vine.

Yard and Garden October 25, 2014

Q.

I hope you do not mind me emailing you, but if am very worried I may have hurt the Concord grape vine in my backyard. I recently moved into a rental property, with a large Concord grape vine. The vine was very overgrown and the fruit has been falling everywhere. The fallen fruit was attracting many insects, and dangerous to my pet dog, and making the garden unusable. I recently cut the vine off the porch (the root is a good 6 feet away in the garden soil). After cutting it back I read that this is a bad time to prune, I am worried about the effect the frost will have on the newly pruned ends. Is there anything I can do to help it?

-Helen C.

NYC

A.

Thank you for writing. The climate and soils of New York City is quite different from New Mexico, but the question is relevant for New Mexico gardeners.

Your grape vine is probably not badly injured. Pruning may stimulate new growth, but this late in the season and because the Concord grape is an American grape adapted to the climate of both New York and New Mexico, it is unlikely that new growth will be induced. Even if it does begin to sprout, it should produce relatively little new growth. The concern is that new growth draws stored food from the vines and will be killed by early frosts, depleting the stored food. Since any growth that develops should be minimal now, the impact on stored food in the stems will be minimal. The rest of the vine is going dormant and can withstand freezes. If growth does occur, the frost will just prune the new growth for you. In the spring you can prune the vine back to new, healthy stems.

Pruning in late summer/early autumn while leaves are still on the plant also removes some of the photosynthetic potential for the vine, but at this late date, the leaves will soon be falling and providing no significant photosynthesis.

I checked the weather/climate information for New York City and, while you are behind New Mexico regarding the approaching winter, the shortening days and cooling nights should prevent significant new growth. New Mexico gardeners in Northern and Central New Mexico will have even less concern that vines pruned now will cause injury. Never the less, spring pruning is a much better choice.

Since the crown of the plant (where the vine and root join) was some distance from the point of pruning, there should be sufficient vine left to produce new growth in the spring. If you had cut it to the ground, the effect would have been more severe, but the vine may still have sprouted in the spring.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

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