Winter Care for Trees and Shrubs
When the cold winds blow, you may head indoors and forget about your landscape. Although many trees and plants can handle whatever winter brings, some may not be as immune to troubles as you imagine.
Here are some things to look out for.
Probably the top concern, especially for newly planted evergreen trees and shrubs, is desiccation.
This is a result of transpiration of moisture. Drying winds, sunshine, low humidity combined with an evergreen that does not lose it’s leaves like the deciduous trees can result in problems. This is compounded if the ground is frozen so the plant can’t take up moisture to replace what is being lost to the sun and wind.
Maples and other trees that lose their leaves in fall are at rest, perhaps you could call it hibernation, in the cold season. But evergreens, especially those with big leaves such as magnolias, rhododendrons, etc., keep breathing and absorbing water and nutrients (although the growth rate will be minimal or nil in the coldest weather). Planting these where they get afternoon shade is a good thing. One of the most helpful preventative measures against desiccation is to make sure the plant has sufficient moisture during the fall going into winter. If it was drought-stressed to begin with, these winter trials may result in death. Newly fall planted evergreens are most likely to have this particular trouble.
Another problem in winter (the opposite of too little water) is wet feet. Too much water standing around plants, as well as in the planting holes that don’t drain well, can drown delicate roots. This causes more winter loss than lack of moisture the balance of the year combined when it comes to trees and shrubs.
Sun scald and frost cracks are two other problems, and somewhat related. Sun scald happens when the tender trunk of a tree is heated by hot (this is “relative” as we’re talking winter sun) sunshine at a time when the wood may be frozen from a very cold night. This can cause some of the bark to separate from the trunk as it expands. These injuries can let in insects and decay and be hurtful to your trees. Painting tree trunks with a white or light latex paint can help lessen the likelihood of sun scald. Also, at planting time, putting the tree into the ground with the same side facing south (if you can determine this) will reduce the liklihood of sun scald. Creating shade somehow would also be helpful. Perhaps shade cloth, burlap, or tree wraps, or anything to keep full sun off frozen tender tree trunks.
Frost cracks are somewhat alike sun scald. These happen as the bark constricts or tightens during cold weather. At some point, tree bark may not be able to tighten any more, and a vertical crack will appear in the bark. Usually the next summer trees will grow back to cover the cracks, but sometimes they don’t. (Perhaps you’ve been walking in a wooded area on a very cold day with snow on the ground and not a sound…then suddenly you hear some popping and cracking, even when the wind isn’t blowing. Most likely this is some tree bark developing a frost crack. The sound can even be loud as that of a small caliber firearm discharging.)
Cold intolerance is another issue. This happens when you’ve planted a tender plant not recommended for your area, or when the temperatures go way up and down rapidly, especially in early fall or late spring.
The result is usually tip or twig die-back. But the whole plant can die back to the ground, or even die altogether if it is not hardy. Die back will kill flower and fruit buds on those trees and shrubs that bloom and fruit on old wood. Some, ofcourse, flower and fruit on new wood, such as beautybush, butterfly bush,
summersweet, pomegranates, and figs for example. Those plants may still bear some after die-back of limbs.
Root injury. Trees with tender and shallow roots, especially recently planted items, may be more prone to root injury than established trees and shrubs. Azaleas, crepe myrtles, Southern magnolias are some that come to mind that have shallow roots that might be damaged in bad winters. Having mulch under the limbs covering the roots is helpful, no matter if the roots are at the surface or a few inches underneath it.
Rodent and deer damage in winter can be troublesome, especially to younger plants. Deer love tender twigs and shoots. Apple trees are among their favorite. And when food is scarce, mice and voles will eat the bark from young trees and plants. Wrapping the trunks is helpful in some cases.
Snow can ride over a new tree, break out limbs of older trees. Shaking or blowing some snow off pine and fir trees can be helpful if there is a really big heavy snow. Ice is worse. Bradford pear trees, crepe myrtle trees and pine trees are among some of the worst hit when there is an ice storm.
Salt and other ice melt products can damage trees, even kill them. So, if you live along a street where salt trucks and plows typically run during the winter, you may have damage. Damage can happen both to the foliage (especially evergreen foliage…as the deciduous is usually gone for the winter) from salt spray and splatters and mist, and to the roots as salt melts the snow and the resulting salty water gets absorbed by the soil and tree. Prevention is the best cure. Don’t use salt near plants, or plan ahead and select salt tolerant plants for these type situations. A few tolerant plants would include: Siberian Pea Shrub, Ginkgo, Serviceberry, Ash, Cypress, Yucca, Blueberries, Winterberry Holly, White Oak, Burr Oak, Catalpa, Sycamore Maple, Horse Chestnut and Honey Locust. Some intolerant plants to salt include: bluegrass, boxwoods, river birch, spirea, Japanese maples and Scarlet oak.
Check stakes and tie-down of your landscape trees. Have the stakes become uprooted, or the string or wires gotten loose? Replacing a stake, or tightening a wire are things that you might want to look about.
(Of course, don’t forget to take off wires and strings as the plant gets older, for these can girdle a tree and potentially kill it as it tries to grow around the wire or other object.)
And let’s mention pruning. Some plants need to be pruned after flowering in the spring. But for most trees and woody plants, it’s safe to prune in winter. Just pick a day when the limbs would not be frozen, after the leaves have turned color or fallen and before new buds break forth in spring. Selective pruning is what you are looking to do, shortening a few branches, thinning out weak or crossing limbs, removing dead and broken limbs, etc. Topping of large trees is a butchering process that I do not recommend, period.
Most of these chores are quick and easy things you can look after or take care of, and even in cold weather we all want to get outside for a few minutes anyhow. Enjoy the break from lawn mowing. Bundle up and go for a walk in the snow. Enjoy the beauty of winter. But, it’s okay to begin dreaming of springtime.