A few weeks ago I wrote about winter damage to English ivy after receiving several calls and questions from concerned homeowners.
English ivy isn't one of the plants in my landscape, so at the time I wasn't aware of the extent of the problem, but I have since noticed that the ivy isn't the only plant affected from last winter's extreme cold temperatures.
Most plants experience some amount of winter damage here in northeast Ohio. You can't have our winters without losing a few plants once in a while, but this year even those old tried and true shrubs and groundcovers have shown extra symptoms from winter's effect.
The most common injury is called winter burn. Leaves on various evergreens will look brown or yellow, as if they had been bleached. In addition, several leaves will drop off of the plant. Many people think winter burn is caused by freezing, but these plants are tough and are used to exposure to cold temperatures.
What actually causes winter burn is when the ground is frozen so long that the plant's roots don't have time to take in enough moisture to counter the evaporation of water from the leaves. Even in winter, evergreen plants need water. Winter winds and sun reflecting off of the snow will cause evaporation to occur faster than under normal conditions. When the roots are unable to replenish the water, the leaves suffer from winter burn.
Plants affected can include landscaping shrubs, such as rhododendron, azalea and boxwood, as well as the familiar English ivy.
According to The Ohio State University Extension Buckeye Yard and Garden Online (bygl.osu.edu), other factors also should be considered when trying to figure out what happened to your winter-injured plants.
On some plants, those injuries could be the result of chemical burn. If the plant is near the roadway, it is possible for salt brine to have splashed onto the plant during winter road management. Chemical burn from salt injury also exhibits the same symptoms as winter burn; yellowing or browning, leaves that appear dry and crispy and even leaf drop.
Although salt damage is usually evident only on the side of the plant closest to the road, winter burn also can appear to be on one side of the plant, the windward side.
The educators at OSU Extension explain that parts of the plants that are below the snow may not be affected because the snow acts like a blanket, protecting the leaves from winter winds.
Winter burn and salt damage injures leaf tissue and cannot be reversed, but that doesn't mean the entire plant is dead. Remove the damaged leaves by gently raking, making sure not to injure the tender new shoots that could be growing from below, or prune away dead vines and branches.
If the damage has caused bare spots in blankets of English ivy and other groundcovers, you can replant cuttings in those areas or let the plants fill in over time.
The best attitude to take when the weather has caused havoc in a landscape is to simply wait and see. If a beloved tree or shrub is lightly damaged, it will probably recover. If it doesn't, then it's time to remove it from the landscape and start over.