Tree Talk: Salted Evergreens

Fallen trees have been removed, power has been restored, and people are back in their homes. For those of us in Westchester County, the effects of Hurricane Sandy have passed. Or not.

Since mid-November, I have been seeing an unusual level of salt damage to evergreens. While winter road salt always has a bad effect on many evergreens, the damage I’ve noticed recently is far more extensive. One of the effects of Hurricane Sandy was to carry salt spray from the ocean and drop it throughout our area. The northeast winds gave many of our shrubs a thorough drenching of salt water. Throughout the towns bordering Long Island Sound, we have been seeing extensive salt damage, particularly on the northeastern and eastern facing sides of evergreens. Many white pines that were near the ocean are entirely brown and desiccated on their eastern sides. This is true of plants several miles inland as well.

How can you tell if your evergreens have experienced salt damage? Take a look. If the plant or tree was green last fall and now has browning needles and dry tips, salt is a likely culprit. When salt coats the foliage of a plant, it draws moisture out, causing a burned effect. Warming temperatures after the storm can also have this effect. If damage is extensive, the plant will die. If the buds are brittle or broken and easily snap with light pressure, the entire branch is probably dead. Once needles are brown, they never return to green again. However, I caution people to wait until spring before making any decision on removing the plant. This type of damage is new to us, so we don’t have a clear idea of how the plants will rebound.

Is there any way to restore a damaged evergreen? Maybe. If green needles are mixed in with the brown, cross your fingers  and hope that the plant will rebound on its own. If the plant is heavily desiccated, including the buds, we can go back into the canopy and feather prune to where we find green cambium. This is labor intensive, but it can force the dormant lateral buds to grow out. Not all evergreens can be forced this way; there’s little we can do to assist plants such as hemlocks or others that won’t respond well to severe pruning.

I usually recommend several applications of anti-desiccant spray to broad-leaf evergreens during the winter; it can also help needled evergreens retain moisture. I find it makes a big difference in our area, not just for salt burn but for winter burn in general. The freeze-thaw cycle that we go through in the New York Metro region is extremely tough on evergreens. (Does 5 degrees one week and 45 degrees the next week sound familiar?) A plant health care professional (such as Almstead) can take care of this; they will have the equipment to reach tall shrubs. If you apply the anti-desiccant yourself, make sure it’s on a day when the temperature is above freezing. Also, be aware that certain anti-desiccants should not be used on some evergreens such as cypress, arborvitae, cedar or juniper. Read the label and know the species of plant you are treating: conifer leaves can be broad-leaf, needle, scale-leaf or awl-like, and can’t all be treated the same way.

Salt in the ground is a different problem. Since Hurricane Sandy gave us a one-time application, any salt in the soil should dilute with the spring rains and snow melt. You may want to delay fertilizing this spring if you use a generic, synthetic fertilizer. This type of fertilizer contains salt; hold off until we’ve had some thorough soaking. Organic humates will bind the salt in the soil; there are actually products designed for this type of soil, geared to areas that experience seasonal flooding.

A sudden salt drench from a hurricane is unanticipated. If, however, you live near the water (or near a heavily salted road), choosing salt-tolerant plants is wise. Some plants, such as black pine, blue spruce and Chinese juniper will tolerate a lot of salt. I always recommend choosing plants that are comfortable in your location rather than trying to maintain a plant outside its natural environment.