With winter around the corner people are preparing to winterize. Agrologist Sherri Roberts says this practice should extend to trees as well.
With elm pruning bans lifted, Roberts reminds homeowners to ensure tree branches are trimmed around the home, especially the roof.
“If you've got any branches that are extending out over your roof, get them cut off, because you are risking your shingle health, which is then in turn risking your whole roof health, and once you lose that roof, I mean, hey, your house is going to end up an absolute mess.”
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Preparing trees for winter is about more than preventing damage, Roberts offers reminders to care for trees before winter to ensure they remain healthy. One aspect of this includes thoroughly watering evergreen trees.
“Evergreens transpire water throughout their scales or needles all winter long. If you don't have them well watered going into winter, then you're just asking for them to brown out on you. Keep watering them until the ground's frozen.”
Anti-transpirant sprays can be used to prevent drying out. Roberts mentions these as great for trees with an affinity for drying out, such as dwarf Alberta spruce.
Any trees less than four inches in diameter may also need help getting through the winter, Roberts recommends tree wrap on all such trees in the fall to prevent sunburn and winter burn.
“They actually will get a winter burn because the bark is so young and tender. The sun's on the ground, the sun reflects off the snow and it warms up the cells in the tissue in the bark that's facing the sun. Then those cells start to move and then at night, the temps dive down cold and then those cells freeze.”
Neglecting this aspect of young tree care can result in the tree being weak at maturation.
“You'll see them start to crack and the bark will start to peel off. It's an injury that happened when they were young, but as that tree starts to spread out in its diameter and grows, then because of those cells that died because of the cold, damage shows up. I'll go out to people's yards, and they'll say, ‘what can I do about this?’ There's nothing; the injury happened when it was young.”
Tree wrap is a corrugated thin sheet with a shallow layer of tar that is wrapped around a young tree. It protects the bark during the winter and is taken off in the spring. This should be done annually until the tree is more than four inches in diameter.
Roberts also emphasizes not using nitrogen fertilizers to trees this time of year as it encourages new growth which won’t have time to harden for winter.
“If you fertilize with nitrogen late, you encourage this new growth. Then mother nature came along with the freezing cold temperatures and said, not on your life. That's what happens, they die back.”
Die back refers to when trees gradually die, typically beginning from the tips of the tree and moving inward.
Roberts reminds gardeners that they’re not done yet, there’s plenty more to do until frost hits the ground.
“Enjoy fall because folks, we know what's coming.”