When cold weather hits, most of us focus on winterizing our garden beds, draining hoses, and blowing out sprinkler lines. But there’s one crucial item that often gets left off the fall prep checklist: your young and thin-barked trees.
Here in Northern Colorado, our trees face a unique challenge. While we love Northern Colorado for its 300+ days of annual sunshine, those bright, clear winter days—combined with high elevation and snow reflection—make our local trees especially vulnerable to severe, lasting damage.
Here’s what you need to know about winter sun scald, why NOCO winters make it so prevalent, and the easy "candy holiday" rule to keep your landscaping safe.
What is Sun Scald? (And Why Colorado Sunshine Can Harm Trees)
It sounds backward, doesn't it? How can sunshine harm a tree in the middle of winter?
It all comes down to drastic temperature swings. On a clear, freezing Fort Collins day, intense high-altitude sunlight—especially when bouncing off fresh snow—heavily warms up the south and southwest sides of dark tree bark. This warmth tricks dormant cells just beneath the surface into "waking up" and activating.
The problem happens as soon as the sun dips behind the Front Range.
When night falls and temperatures plunge back below freezing, those newly awakened cells instantly freeze and die. Come spring, as the tree tries to grow, the dead bark snaps open, leaving ugly cracks, exposed wood, and open wounds. This damage is called sun scald (or frost cracking).
The Solution: A Simple Roll of Tree Wrap
Fortunately, stopping sun scald is easy and inexpensive. Wrapping your tree trunks before cold weather settles in acts like a light-reflecting coat.
Tree wrap blocks harsh UV ray heat and regulates trunk temperatures to prevent rapid thawing and freezing.
If you’re wondering when to put wrap on and when to take it off, just remember the two big candy holidays: Wrap goes on around Halloween, and gets taken off around Easter.
How to Wrap Your Tree Step-by-Step
1) Start at the Base: Begin wrapping at the very bottom of the trunk, slightly below the soil line.
2) Wrap Upward: Move up the trunk in an overlapping spiral (overlapping by about 1 to 2 inches with each turn) to keep moisture from seeping under the folds.
3) Stop at the Branches: Continue wrapping until you reach the lowest main branch.
4) Secure the Top: Fasten the wrap securely using weather-resistant tape (avoid taping directly to the bark). We recommend using electrical tape.
