When people think about tree care, watering usually comes to mind during the hot summer months. But along the Colorado Front Range, one of the most important — and often overlooked — times to water trees is actually during winter.
Long stretches without precipitation and with low humidity can leave trees severely drought-stressed by the time spring arrives. Trees that receive supplemental water through irrigation systems during the growing season are not receiving that water when those systems have been shut down for the winter. Proper winter watering helps trees survive harsh drought conditions and come back strong for the growing season.
Below are the best practices homeowners should follow to protect their trees through Colorado’s dry winters.
Why Winter Watering Matters
Many trees in the Front Range suffer from winter drought stress. Unlike regions with consistent snowfall and soil moisture, Colorado winters are often dry with extended periods of warmth, sunshine, and wind.
Even though trees are dormant, their roots are still alive and require moisture. Without enough water, trees may experience damage to their root system, which results in:
- Winter burn on needles (conifers)
- Branch dieback
- Increased susceptibility to pests and disease
- Delayed or weak leaf or needle growth in spring
- In severe cases, tree decline or death
Newly planted trees and evergreen species are especially vulnerable to winter drought stress.
Please see my blog post: How the Drought Is Affecting Trees on the Colorado Front Range for more information on the impacts on trees during the current drought.
When to Water Trees in Winter
The key is watering during mild periods when the ground is not frozen or covered with snow.
Follow these general guidelines:
- Water once or twice per month from October through March if there has been less than 1 inch of precipitation in a 30-day period (see: 30-day Precipitation Map)
- Choose days when temperatures are above 40°F.
- Water midmorning, allowing moisture to soak into the soil before evening temperatures drop.
Avoid watering right before a big temperature drop and cold period, as frozen water on the surface can act as a “cap” and prevent necessary gas exchange between the air and soil.
How Much Water do Trees Need
General recommendations
Newly planted trees (0–4 years):
- 10–15 gallons per inch of trunk diameter (at chest height) per watering
- Apply water slowly to allow deep absorption
Established trees:
- 5-10 gallons per inch of trunk diameter (at chest height) per watering
- Water the soil beneath the canopy and slightly beyond it
Calibration
To calibrate the amount of water used, turn the water on at a low pressure, and record the time that it takes to fill a one gallon jug. For example, if it takes 60 seconds to fill a gallon, a 15 inch diameter Colorado blue spruce would require 75-150 minutes of watering at that pressure.
15 inches x (5-10 gallon/inch) = 75-150 gallons of water
1 minute/gallon = 75-150 minutes of watering
Where to Apply the Water
Avoid watering directly against the trunk. Instead, apply water to the dripline area, where most of the feeder roots are located. I usually start around the dripline, and apply about 75% of the total water in or just outside that area. Then I work towards the trunk, and apply the remaining 25% within the dripline area.
Proper watering methods include:
- Root Feeder (don’t insert too deep)
- Slow trickle from a hose
- Soaker hoses
- Tree Bubblers
The goal is slow, deep saturation that minimizes runoff, rather than quick surface watering.
If using a Root Feeder, do not insert the tip of the probe more than 4-6 inches below the soil surface. Most feeder roots are within the top 10-12 inches of top soil, and inserting a probe below this level will miss a majority of the feeder roots you are trying to water.
Trees That Need Winter Watering the Most
While all trees benefit from adequate moisture, some species require extra attention in the Front Range climate:
Evergreens
- Pines, including Austrian, ponderosa, limber, and southwest white pine
- Spruce, including Colorado blue and white spruce
- Fir, including white fir
Evergreens continue to lose moisture through their needles during winter, making them particularly vulnerable.
Newly planted trees
- All species
Newly planted trees have lost a significant amount of their root system during the transplanting process. They require good growing conditions and time in order to recover. Generally speaking, trees take around 1 year per inch of trunk diameter (when it was planted) to become established. A tree that was 2.5 inches in diameter would take 2-3 years to establish if all else is good.
Naturally riparian trees
- Cottonwood and willow
- Silver and Freeman maples(‘Autumn Blaze’)
- Alder and birch
These trees are more susceptible to winter damage and benefit from proper winter watering.
Additional Winter Tree Care Tips
Watering is just one part of winter tree protection.
Homeowners can also help their trees by:
- Applying 2–4 inches of mulch around the base (but not touching the trunk)
- Protecting young trees from sunscald and frost cracks by wrapping the trunk.
- Proper structural pruning to avoid large breaks or cracks due to snow loading or wind.
- Avoiding salt damage from ice melt products on sidewalks and driveways
Proper winter care significantly reduces stress heading into spring. See my blog post: Getting a Newly Planted Tree Started for more information on mulching and trunk wraps.
Don’t Let Winter Drought Damage Your Trees
Healthy trees add beauty, shade, and value to your property — but Colorado’s dry winters can take a toll without proper care. Consistent winter watering is one of the simplest ways to help trees survive and thrive in our Front Range climate.
If you’re unsure how much water your trees need or want help protecting your landscape this winter, the Certified Arborists at Patriot Tree Company can evaluate your property and recommend the best care plan. Our team is dedicated to helping your trees stay strong and healthy in every season.