A northern Minnesota winter can be hard on apple trees. In my case, when the snow melted it revealed that two of our trees were completely “girdled” and a third was partially eaten. Girdling kills trees. It means that something (vole? rabbit?) had gnawed off the bark around the entire trunk of two trees in a swath about 2” wide.
These trees are our yummy Honeycrisps, a variety developed right here in Minnesota. We had bought the trees three years ago from Gilby’s Apple Orchard in Aitkin, from orchardist extraordinaire David Gilbertson. David recommended bare root dwarf trees, grafted to B9 rootstock, planted close together and trellised. We got three, put them in the ground, and they started bearing a few big delicious fruits in their second year.
I called Gilby’s with the bad news, and asked if they had any more dwarf Honeycrisps available. David said instead of buying new trees I should try a “heading cut”—cut off the top of the girdled trees and see if they will grow new branches from under the cut (one of which would eventually become the new leader). It looks severe and after a week no new branches have emerged, but there is hope! (More specifics in the full interview below)
David Gilbertson agreed to be our guest for Local Food on the Wednesday Morning Show this week. He offered a list of tips for coping with winter damage and preparing apple trees for summer:
- First, inspect for winter damage. If a branch has broken, David recommends a “Dutch cut.” And if the bark is ripped down underneath, you can secure the bark back to the tree (even using duct tape). “If you can do that soon enough, believe it or not it will heal and it will be fine. After a few months you’ll be amazed at what it does.”
- David says it’s ideal to prune apple trees in March or early April, but there’s still time this spring if you haven’t gotten it done yet. “It’s all about air flow through your trees. Prune your trees so you get really good air flow. If you have really good air flow you’re going to end up with not nearly having the fungal conditions that you’re going to have if you have a very dense canopy…A happy leaf is a dry leaf. And if the leaves were always dry you would never have to worry about fungal issues. If you don’t’ prune your tree it’s going to be a denser canopy, the leaves are going to stay wet longer, and you’re going to be more susceptible to fungal spores.
- The next thing to think about is feeding your tree. “Now is the time to get that granular fertilizer on your tree…Even being able to put on some 10-10-10 or 10-10-10 and micronutrients is really a good thing right now. But it is so important that you only feed the tree April, May, and June. You do not feed the tree as of July.” A lot of people make the mistake of using a fertilizer stake or something where the tree is being fed into July or later. “that would probably be the worst thing you could do for your tree because as of July 1st or summer solstice, you need that tree to start shutting down, believe it or not, and getting ready to go to bed.”
- Another key principle is thinning the fruit. “Thinning is equally as important as pruning…You’re going to have these beautiful blossoms, you’re going to have great pollination, and now you’ve got all these little ‘fruitlets.’ A fruitlet is a little apple about the size of your thumbnail. You’re going to have something called the ‘king fruit’ in the middle, which is larger, and you’re going to have 4 or 5 subordinates around it. If you want to really strive for quality fruit this year, you want to get rid of all those subordinates around that king fruit, and you want one king fruit per fist. So if you would just imagine your fist, you would want one king fruit at one end of your fist and another king fruit at the other end of your fist. If you do that you’re going to be amazed at the quality of fruit you generate on your tree.”
- Finally, tree trunk protection is important, protecting the trunk from sunlight in the spring and from predators.
Gilby’s nursery has grown over the years, and now ships bare root fruit trees to 8 states in the Midwest. “We’re excited about our new shipping model because people are able to take advantage of some of the trees that we have [that are not available elsewhere]. We had a customer yesterday that said ‘I’ve been trying to find this type of tree on this type of rootstock, and we finally found it at Gilby’s’”