Assessing Winter Damage
First, don't panic. And don't do anything too quickly. Some plants "wake-up" for the spring a little slower than others, so be sure to give your plants time before yanking them out of the ground! One test you can do on trees and shrubs is to scratch a few twigs with your fingernail and see if the cambium layer (the layer just under the bark) is green. If it is whitish-green to green, the plant is still alive - even if it hasn't leafed-out yet. If it is yellow or brown underneath, the twig is dead. Using this method, you can gradually work your way down the branch toward the main trunk to determine if the entire branch is dead and should be removed.
Here are some of the most common problems caused by the winter season:
1) Broken Branches. Ice, snow, and wind can cause branches to bend and break over the winter. How do you fix it? You will need to prune off these damaged branches. Always prune back to live, green, healthy wood. Prune to a bud, stem or trunk - don't leave any stubs! If pruning is not done properly, it can cause more damage than good. Click here for specific instructions on how to prune. How can you prevent it next year? Broken branches are not entirely avoidable, but the amount of damage can significantly be reduced by thinning the canopy of dense trees and removing branches that have narrow branch angles. Also, avoid piling excessive amounts of snow on trees and shrubs.
2) Dessication. This type of damage occurs when a plant's foliage dries out from sun and wind, or when a lack of available moisture is caused by frozen soil. In our area, damage is most commonly seen in Boxwood, Dwarf Alberta Spruce, and Arborvitae; but all evergreens are susceptible to damage. Dessication is identified by browning, usually tips of needles are affected first, but in extreme cases entire needles and possibly even small branches may die back. How do you fix it? If dessication damages are minor, with only minimal needle tips showing damage, no further action is necessary. But if damage is more severe, you will need to prune out the dead foliage, so the plant can concentrate its energy towards new growth. But again, do not prune too early in the spring. It is better to wait until the chance of a late frost is over, to prevent further injury. How can you prevent it next year? Be sure to water your evergreens in the late fall (especially if it has been drier than normal) to give the roots a little extra moisture to make it through the winter. Also, be sure to use an anti-dessicant, like Wilt-Pruf, in the fall. This will prevent moisture loss in the foliage, and can significantly help your evergreens through the winter!
3) Animal Damage. With so much snow on the ground this year, the deer and rabbits have been seeking food wherever they can find it - probably in your backyard! You may notice nibbled-off twigs, girdled trunks, or bark that is scratched or torn off. How do you fix it? For trunk wounds, it is usually best to just let the tree or shrub heal itself. If trunk damage is extreme, please contact us and we can help you determine if the plant should be removed. Watch for signs of insects through the spring and summer, as injured trees are more susceptible to insect damage. Promptly treating insects with the correct insecticide will protect your trees and shrubs from further damage. For damaged twigs and branches, prune as described above. How can you prevent it next year? Use a tree wrap to protect the trunks of your trees, especially new or young trees. You can also put chicken wire around any shrubs that are especially fragile.
4) Salt Burn. Road, walkway, and driveway runoff is usually full of salt in the winter. If this runoff gets near your planting beds, you may notice plants this spring with dried, burnt-looking leaf edges. How do you fix it? Where runoff is unavoidable, flush the area around the plants in early spring by applying 2 inches of water over a 2-3 hour period, repeating 3 days later. This will help to leach the salt from the soil. If salt spray from the road is a problem, use water to rinse the foliage and branches of any affected plants. For branches that burn despite the rinsing technique, you should prune out the damage as described above. How can you prevent it next year? Don't pile snow containing salt around plants or trees or put it where runoff might reach plant roots. Try using sand instead of salt on walkways that are near planting beds.
5) Sun scald. Sun scald occurs on sunny days in winter when the bark of the tree is warmed by the sun, then when the sun sets and the temperatures quickly drop, the bark and tissue are not able to reacclimate to the change quickly enough. The result is death or damage of tissue, and you may then notice cracking, separating, or badly discolored bark (usually on the southwest side of the plant). How do you fix it? As described above, there is no need to treat this open wound, the tree will eventually heal itself. But again, watch for insects and fungal infections, which are more likely when the tree is weakened. How can you prevent it next year? Wrap the trunks of your new and young trees with a light colored, breathable tree wrap. It is best to wrap from the soil line up to the first set of branches. This wrap should be removed in early spring.
Let us know if you have any questions on anything you've read here, or if you'd like more information on any of these topics.
Our maintenance department would be happy to come out and take a look at any trees or shrubs that you think may have been affected by any of these problems. Click here to contact us!