Seriously? Just three short weeks ago I was all doomy-gloomy about chilly temperatures so much so that I even advertised my next article (the one you are reading now) as to how cold temperatures can affect our fruit trees and now we have had a prolonged stretch of warm and dry weather.
Mother Nature seems to play this trick on us almost every January, getting us excited about spring and then surprising us with a blast back to winter. So now, of course, this week the weather has returned to lows hovering around zero with new snow in the mountains.
Winter in our area is never short of surprises (and frustrations, and potholes, and yes, plenty of smiles). But I digress, as the fruit trees are the topic this week, not my thoughts on the weather.
In late 2010 (and early 2011), temperature readings throughout Southwest Colorado registered minimums ranging from minus 32 to minus 14. Most of our fruit trees apples, pears, apricots and plums can survive these temperatures. Many are rated for Hardiness Zones 2 and 3, which should be adequate for survival. However, if your area had temperatures as low as minus 25, there is a greater chance that some fruit tree(s) mainly, peaches and cherries did not survive. Additionally, there is still a chance that even though the tree itself survived, a number of the fruit/flower buds did not.
For example, those of you who have apple trees that typically produce thousands of small apples every year, this could be a blessing. Cold temperatures can act as a fruit-thinning mechanism, reducing the number of blossoms on the tree. As long as a cold snap in spring (this happened in 2010) doesnt occur, you may actually harvest tastier and larger fruit.
The challenge in predicting damage to trees and blossoms is the numerous variables that determine survivability. In an ideal world (yeah right, remember where we live) trees would have adequate moisture in September that tapers off during October and early November, followed by a stretch of cold temperatures in late November and early December. Essentially, you are trying to minimize the stressors, while winterizing the tree by putting it into a deep dormancy.
Worried that there may be damage to the flower buds? You can always take a couple of samples from your fruit tree. Because this is also a good time to prune trees, look for buds on branches that you would otherwise be removing. Place the pruned twigs or small branches in water and let sit for three to five days. Then, using a razor blade or sharp knife, dissect the bud vertically and examine the flower bud. If you see any browning inside the bud, and not an overall greenish color throughout, then the bud is damaged and will most likely not set fruit.
If you are purchasing a new fruit tree online or, better yet, from a local nursery, do some research as to where the cultivar was developed. Look for those that come from the upper Midwest or Northeast, as they just like the people are as cold-hardy as you can get.
firstname.lastname@example.org or 382-6464. Darrin Parmenter is director and horticulture agent of the La Plata County Extension Office.