Normally Denver temperatures average 57°/33° in April. Denver International Airport fell to 10 degrees Fahrenheit April 13, 2022, setting a new record low—the coldest Denver temperature this late in the season since 1953.
9News.com reported Denver has the lowest average dew point temperature ever recorded for April. And the state has had the most high wind warnings on record to this point in a year.
For homeowners who did a little early revenge planting (to counter the winter blues), it was likely a bust for newbie plants and trees.
Denver's USDA Hardiness Zone is 5b-6a…a fact that determines if your chosen plants and trees are likely to thrive.
For details on temperature fluctuations and frost injury to trees and shrubs, see the Colorado State University Extension’s fact sheets on Environmental Disorders of Woody Plants and Evaluating Tree Fruit Bud & Fruit Damage From Cold, and Colorado Gardening: Challenge for Newcomers, which explains how temperature fluctuations in Colorado affect our gardens.
The Colorado State Forest Service reported, “with warm weather preceding winter last year, the trees did not have the chance to transition into dormancy before freezing occurred. Large shifts in outside temperatures (in April) exacerbated the damage.” Unfortunately, according to the CSFS, there’s not much that can be done, except to wait and see what happens to the trees later in the season.
America’s Handyman Bob Vila recommends that deciduous trees can be planted in soil that has hovered around 50°F for several days. Evergreens need to be planted in soil that's been stable at 60°F. Donovan Arborists can advise when trees should be planted with certainty.
And before you dig, call 811 to have your utility lines marked for free. Seriously, call. Hitting an underground utility line with a shovel can be deadly.