If you planted a soft-barked tree like a maple, cherry, weeping willow and various fruit trees, you need to take some action to help prevent Southwest Tree Injury. First of all, what is Southwest Tree Injury? Southwest Tree Injury occurs when a young soft-barked tree, with exposure to the sun from the southwest, experiences winter weather and sustains damage.
During the day, the sun warms up the bark, causing it to expand. Then at night, when it gets cold, or perhaps freezes, the bark cools down and contracts. As this process repeats again and again over the winter, the bark breaks down and really never recovers.
To see an example of this, just drive through any of the large big box store parking lots and look at the tree trunks. Invariably, their bark is split open on the southwest side of the tree. It’s kind of unsightly and the wound leaves the tree open for disease or insect damage throughout its life.
Luckily, there is an easy way to prevent this from happening. You just need to go to your favorite nursery and get some paper tree wrap, then loosely wrap the bark of the trunk of your newly planted tree. This will keep the direct sun off of the bark and help to minimize the problem. Take the wrap off in the spring, but plan on repeating this the first 2-3 years.
Also, if you haven’t already, you should place about a 3-inch layer of mulch around your tree, being careful not to put the mulch right up next to the bark. This mulch layer will help to keep the roots warmer and will also help to retain moisture in the soil.
Speaking of roots, your trees may look dormant on the top, but the roots will be actively growing so you will need to make sure your new tree plants have water throughout the winter. Just keep an eye on the rainfall and supplement by watering so that your new trees get about an inch of water each week.
Also, if your tree is a little top heavy or planted in a windy location, secure it with a couple of stakes for support. Be sure to secure them to the tree loosely so that there is a little bit of movement back and forth.
And there’s no real reason to fertilize the newly planted trees until springtime. Fertilizer can stimulate growth in the top part of the tree, but during the winter, you really want it to concentrate all its energy in developing a good root system.
If you haven’t planted any trees or shrubs this fall, we have some recommendations for trees that do well in Oklahoma on our website (tulsamastergardeners.org) in the Trees portion of our Lawn and Garden Help section. Good luck!
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You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th St., or by emailing us at email@example.com.