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Yes, growing wine grapes is possible in the North!
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Wines And Vines In Cold Climates
Squeezing Results From Northern Grapes
By Colin Beckingham, it4gh.com
Last year I made one half litre of wine from pressing my own grapes. That's hardly a significant boast after 14 years of experimenting, but to me it is a significant achievement considering all the hardship and learning taken to get to this point. I'm growing my vines in a borderline hardy area of the Canadian Shield in poor soil, doing my best as the temperatures flirt with -35 degrees a couple of times in a normal winter, and -40 degrees about one winter in twenty.
At first I thought I was doing well. My own cuttings of 'Fredonia' rooted well, quickly became established and produced a few grapes within 5 years. They grew sturdily and often volunteered shoots but only rarely flower clusters. Then there came the great cold, I think it was the winter of 2000. None of the buds grew on any of the vines. I thought the vines had been totally killed. But after weeks of waiting eventually a few buds started to sprout about an inch from the soil surface. All the vines eventually came back to life, sprouting from soil level and leaving a large network of old canes that remained bare. They have taken even more years to re-establish themselves after this big freeze.
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‘Frontenac’ is an excellent and hardy wine variety
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I came to learn that there are several stages to freezing in grapevines:
First comes the destruction of the flower cluster in the dormant bud. The evidence that this has happened is easy to see; many buds open in spring and produce healthy leaves, but none of the buds produce flower clusters. This seems strange; the buds are good and fat and seem very promising.
Next follows freezing of the bud itself so that no shoot emerges in springtime. Again this is easy to see; the buds do not open, except maybe a few that are close to the soil surface and had been protected by the persistent snow cover or other deliberate mulching. Cutting into the vine in springtime causes it to bleed, showing that the cane tissues are still capable of conducting sap, but the leaf clusters do not expand.
At even lower temperatures, the cane tissues themselves will freeze. In this case no sap can be conducted.
And finally the lower areas freeze as well, including roots, and the whole vine is dead.
The actual temperatures at which these events are triggered vary with the variety of grape, the vigour of the vine, the stage of dormancy reached before the low temperature is experienced, and many other factors such as geographic locality, type of soil and so on.
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Grape vines can be beautiful in a landscape application as well
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There is also the issue of cold temperatures after the buds open in spring. We might consider this a separate issue. My 'Frontenac' grapes are subject to this phenomenon - having survived the extreme cold weather of January and February, the buds open early in spring, but later below-freezing temperatures kill the new growth. They then sprout out again within a few days and seem to recover their previous vigour.
Lists of vines that attempt to rank varieties by hardiness seem to be at best only a guide. Individual localities can show significant differences. Some lists show 'Fredonia' is hardier than 'Concord', but in my location the reverse is generally true, particularly where flower cluster freezing is concerned.
Growers can do a number of things to keep the cold off the vines:
Mix the air - since cold air sinks low and warm air rises, large fans can create an artificial wind to keep cold air that would otherwise settle around vines mixed with warmer upper levels of air. This approach works for both winter and spring freezing.
Cover the vines - if the vines can be kept covered against the cold they can be substantially protected from winter freeze. However, this approach is problematic once the vines have been uncovered and have started making growth in spring. The new shoots are too tender to suffer mechanical covering when a late frost threatens.
Natural air drainage - the most favourable sites are sloped to allow cold air to drain away quickly. Buds, canes and shoots may be subjected to brief periods of cold, but they do not last long enough to cause real damage.
Training - there are a number of ways to train vines; these methods will not be repeated here since they are commonly reported elsewhere. However, for the purposes of protection from the cold, a method that puts both canes and buds close to the soil so that they can be covered is an advantage. Then in late spring with the threat of late frosts, a system that would put the emerging growth high out of the reach of the sluggish cold lower down has a clear advantage.
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‘Valiant’ is the hardiest northern grape
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When a severe cold does hit and damage your vines, the worst thing you can do is panic, dig up the vines and go looking for replacement plants. In my experience, if vines survive what is a normal winter in your area, then after a severe freeze it might take until mid- to late June for buds to appear, but if they can then they will come back. By mid-July if there is no sign of growth, then the vine must have been killed. Of course if you can't wait you will buy a new vine, but you will lose the vigour of the root.
Provided the lower parts of the vine canes have not been frozen and killed, even though there do not appear to be any buds alive the vine is able to produce adventitious buds. These buds come from tissues that did not form buds in the previous season, but are capable of forming buds early in the new season. It may take some time for the buds to appear, so keep a close eye on the rootstock and do not interfere with it more than necessary. When the adventitious buds do sprout, however, stand back because the new shoots will be very vigorous due to the imbalance between root and top. This vigour is lost if you simply dig up the vine and replant. The new vine has to start all over again.
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Laying grapes down in fall with wooden posts
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A downside to adventitious buds is that they tend to come out sideways. Eventually when they have strengthened of course you can train them upwards, but they will never have the 'head straight for the sky' form of new buds on new vines. Sideways can be good, if for example you vow to protect your vines every winter from then on, since it won't be as hard to bend the vines down to the ground.
As an aside, my vines do not seem to attract deer. I have never seen deer go for grapevines in my locality, which is a big advantage since I am not restricted to planting them inside the protected garden area. There are reports of deer damaging grapevines in other areas, so do your research and watch your plants for browse damage.
In my hardiness zone, any wine at all is an achievement. Northern gardeners don't expect everything to be easy, but we do insist on sailing as close to the wind as we can, learning a lot in the process, and deriving great satisfaction from our few successes. My new plants are the 'Frontenac' variety. I will be reporting back on the new successes (and failures) in a few months.
Colin Beckingham is a writer and owner of Information For Greenhouses and Horticulture (www.it4gh.com), an organization dedicated to the use of information technology in a horticultural context. They offer software applications and services to the greenhouse and horticulture industries and are continually researching and experimenting with various software tools to assist people in these industries to remain competitive and profitable.
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