Here on the Front Range in Northern Colorado, winters are getting drier with less snowpack. While this might be a great break for your snow shoveling muscles, your trees and shrubs are susceptible to lasting damage. Low humidity, low soil moisture, and dramatically fluctuating temperatures can wreak havoc on a tree’s state of dormancy. This goes for established trees as well as new plantings. What can you do? Winter water!
When to Water
- The daytime temperature should be 40 F or warmer when you water your trees and shrubs. Be sure to water as close to noon (or earlier) as you can so the water has a chance to move through the soil before nighttime freezing temperatures.
- Winter watering should happen between October and March except when precipitation has been good or there is visible snowpack on the ground.
What to Water
- Trees, especially new plantings. The first three years are critical for tree establishment and the shallow root systems of new trees are sensitive to freezing and thawing. Water underneath the branches within the circle bounded by the “drip line.” Water to a depth of 12 inches. Trees should receive 10 gallons per inch of trunk diameter (measured at knee height). Do this once or twice a month.
- Shrubs, including roses, and fruiting varieties. Apply 5 gallons for a small shrub (less than 3 feet), and 18 gallons for a large shrub (more than 6 feet) on a monthly basis from October through March. Newly planted shrubs will require more winter water, twice monthly using these same amounts at each watering.
- Perennials that have been planted in the fall have less time to establish than those planted in spring, so they could use a bit of water during warm dry winters.
How to Water
- Sprinklers attached to a hose. *Do not use your sprinkler system which could freeze your lines!
- Soaker hoses
- Soil needles. *Do not insert more than 8″ down into the roots and insert at an angle
IMPORTANT: In freezing temperatures, hoses left attached to faucets are susceptible to breakage. Water inside the hose expands as it freezes, causing the damage. Always detach and drain your hose after use!
A tip from Dave, our nursery manager:
In dry weather, if there is an extreme cold front moving in, water your trees really well on the last warm day before the freeze. This will coat and fill roots, helping them stay insulated, and the energy put off by the freezing action can actually regulate the soil temperature by a degree or two. Thanks for that Dave!