Winter-damaged shrubs call for patience, then pruning

Freeze damage is easily visible on many evergreen shrubs at the beginning of spring, and the temptation to prune those plants back right away can be strong.

But gardeners should be patient and wait a few months to see how far the damage goes, urged horticulturist Mark Viette, host of the In the Garden radio show and Virginia Farm Bureau Federation television garden expert.

“Not just cold temperatures in the winter, but an early freeze in November and December could also have caused damage to the leaves,” Viette said. “You will see brown leaves on many shrubs, but is it frost damage or something else? The key is to wait and see. It can take several months for evergreen leaves to truly die.

“Sometime in May or June you can feel free to prune out the damaged leaves and branches, because by then you’ll be able to see how far back to cut,” he explained.

Smaller freeze-damaged leaves and branches are best pruned with hand-shears, Viette said, while larger damage can be pruned out with lopping shears. “I really prefer hand shears over the powered hedge trimmers; they give me more control,” he said.

Evergreen shrubs like hollies and boxwoods face numerous challenges when the weather turns cold. Sometimes a plant may not get enough moisture, and the tips of its branches literally die back. Sometimes a plant has been fertilized in the fall or pruned too late in its growing season, and tender new growth doesn’t get enough time to harden off before freezing temperatures hit. Heavy snow and ice storms can cause significant damage to plants, sometimes breaking off major branches. In all these cases garden experts recommend waiting until spring if possible to prune damaged branches. The dead tissue can help protect the rest of the plant from further cold damage until the weather warms up.

“Yews are often affected by cold weather, because they’re often pruned in August and have tender new leaves when cold weather hits,” Viette said. “Gold dust, or aucuba plants, often suffer winter damage. In many areas of Virginia, the tips freeze back. You can take a sharp knife and scrape the bark to see if the limb is still healthy. Be sure to prune out the dead tips back to live tissue.

“You can safely prune these plants back hard. When you’re done, the plant’s going to look a lot better, and you’re going to find nice, fresh growth coming out,” Viette said.

Other winter damage can be caused by hard freezes literally heaving plants out of the ground, and by salt poisoning of a shrub too close to a public road or next to a heavily used driveway or walkway. If a plant is heaved out of the ground experts recommend replanting it as soon as the soil thaws. Mulch it heavily to prevent future heaving problems.

Salt damage can be addressed by flushing the area around a plant with 2 inches of water over a 2-hour to 3-hour period in early spring to leach salt and road chemicals from the soil.

For more garden tips, visit Viette’s website, inthegardenradio.com, or watch him on the Virginia Farm Bureau YouTube channel at bit.ly/itg_viette.