Saturday, June 18, 2011

Edmonton Grapes Spring 2011

Fascinating what the weather and climate does to affect the grape vine.  Last fall we had an abnormal freeze event on the 15th of September.  The overnight low was -6.5 in our backyard and the grapes on the St. Croix vines that were two weeks from being ripe were frozen solid that night (see link to Frost Ends 2010 season).  The grapes were lost having only attained 12-14 brix.  Come spring I was looking forward to a new year, new crop and perhaps normal weather without these 1 in 30 year freeze events.  As it turns out the freeze from last fall did more damage that ending the 2010 crop year.  The vines were not nearly ready for that kind of cold and the freeze damaged the buds on the canes that would be this years crop.  About 70% of the buds were killed off and many canes did not even break bud.  You can see from the picture below that the right side of the vine has some growth with canes about 12 inches long now each with 1 to 2 nice flower clusters, but very little growth elsewhere.  Interestingly I decided to leave the vine to see if it would push secondary buds and while at least 3 weeks later than the bud break on the right side of the vine, there are several buds that have just broke in the last 2 weeks and have 2-3 inches of growth now.  Good thing to wait before pruning.

Even worse was the Edelwiese, not a single bud pushed on last years canes and the vine has died back to the ground.  There is new growth from the base and that's it. I don't think this is winter damage as the cold we received was in the -35 range but all the canes were on the ground as we did the year before and there was at least 2 feet of snow cover. 

What further confirms that it probably wasn't the winter lows that killed the buds but the hard freeze in September 2010 was that the Acadie Blanc vine that is growing against the house, came through the winter with excellent bud survival.  It did not suffer the detrimental cold of the September 2010 freeze as it was against the house and a few degrees warmer than out in the yard.  But the winter lows it would have experienced would have been very similar to the St. Croix and Edelweise, yet it is know as being less hardy than those two vines.  Also interesting is we have nice flower clusters on the Acadie Blanc, 2 clusters per shoot.  It will be interesting to see how the vine and grapes mature in this climate.  See photos below (Acadie vine and Acadie flower cluster)