With the low temperatures North Dakota experienced this winter, I expect to see some damage to the more tender grape cultivars in our vineyard. If your plant doesn’t show new growth by July, it’s probably dead.  But if you have a plant that has grown good for many years, and it appears dead or injured this spring, there is a good chance that it will come back from buds below the soil. Following are a few key things to look for pertaining to winter damage and some steps to help the plant recover.

Assess the plant in early to mid-May. If there are some normal shoots (above, left) PLUS some small buds just opening or nodes with no buds opening, there is winter damage to the vascular system of the plant.

If you leave the plant as is, this is what will probably happen: a. The buds start to grow and then die (above, brown shoots on left side) and b. Vigorous new shoots will grow from the base. (What appears to be green leaves on the top of this plant are actually from the plant in the next row.)

Cut the old plant down at the ground and remove everything old.  Start training 4-6 fresh new shoots up into a fan shape over the summer.  This picture shows how your new green, growing shoots should be positioned to give the plant some air. Use twine to loosely tie the canes to the wires. Train the BEST shoots upward to become possible new trunks. BEST= medium, moderately growing shoots. (Not the smallest and not the biggest.)

It is going to look like a mess! Check the plants twice a week to tie up the rapidly-growing shoots.

The next spring keep one good, medium cane as the new trunk. Cut it off just below the top wire and allow lateral shoots to become the new cordons. Also keep 1-3 canes of last year’s shoots on the lower wire so that they can fruit and use up some root energy.

The following year (third spring), the new main plant with its new trunk and cordons, should fruit.  When you are pruning this new plant, remove the 2 extra canes on the lower wire. (If you still think it’s super-vigorous, you can keep an extra cane, as in this picture above.)

Use your judgement as you go along in this process.  After the injury, very vigorous plants need more shoots kept and spread over the trellis to spread out the root energy. If the regrowth is weak, only keep 1-3 new shoots and train them as above. Do NOT fertilize grapes in this stage. Slower growth is better.

Good luck!

Kathy Wiederholt
Kathy.Wiederholt@ndsu.edu
Fruit Project Manager