The leaves on the trees are changing colors in its typical fall fashion. But with the sudden change in temperatures, they have dropped more quickly than I expected. Enjoy them while they last. Iowa winters can be rough on everyone and everything, but we do what we have to do to get through it. This week, Linn County Master Gardener Judy Stevens describes what you can do to protect one of our most precious resources, our trees.
Q: What should I do to protect my new trees this winter?
A: New trees need a little TLC for the first three winters. One of the biggest threats to a new tree’s first through third winters is the possibility of the bark splitting on the trunk of the tree. This occurs when the tree is frozen and on a warm sunny winter day, the sun warms the bark on one side causing it to expand. The expansion causes cracks and if they are deep or severe enough over the length of the young tree’s trunk, it can be fatal.
To protect new trees from bark cracks, wrap the tree with tree wrapper, which you can find at a good quality garden center or corrugated plastic pipe. If using corrugated plastic pipe, slit the pipe its entire length, open it and place around the tree. The initial placement of the pipe and removal of the pipe must be done carefully so the newly slit edges of the pipe do not injure the bark.
Q: When should the tree wrap and pipe be removed?
A: The wrap or pipe should be removed in the spring as soon as the tree shows signs of budding and leafing out. Leaving this protection on too long will encourage moisture accumulation and possible mold problems. The trunk will benefit from the sunshine and rain of spring.
Q: Will the tree wrap and pipe deter rabbits and deer?
A: Not necessarily. Deer love to rub against small trees in order to rub the covering off their antlers, which can be very destructive. Deer also will eat the branches. Rabbits and small rodents also are interested in eating new trees. They will nibble at any exposed part of the tree low to the ground. Depending on how deep the snow gets, this nibbling could be quite high on the tree. Therefore the best protection is to encircle the tree with a fence. A taller fence may be needed to deter the deer .
Q: What about evergreens? Is there anything I can do to protect them over winter?
A: Much of the winter kill in evergreens is the result of moisture loss from the needles. Winter kill can result in either losing the entire evergreen or having large areas turn brown and die out. Water evergreens this fall up until the ground freezes. This will help get moisture to the needles. When watering, don’t water the tree at the base of the trunk, but at a distance of two times the height of the tree around the tree, otherwise known as the “drip line.”
Another prevention method for small evergreens is to spray the tree with a desiccant spray that will prevent moisture loss on warm sunny days. These sprays work by protecting the leaves and needles of the tree. Products can be found at a quality garden center. However, the spraying remedy may not be practical for large trees.
Questions on gardening, land use or local foods? Contact Michelle Kenyon Brown, community ag programs manager at Linn County Extension, firstname.lastname@example.org.