Trees and shrubs can still need water during a dry Colorado fall and winter, after the sprinkler system is shut off for the season. Colorado State University Extension, based in Fort Collins, covers that on its PlantTalk Colorado page about fall and winter watering, which links to a video on the CSU Extension YouTube channel titled ‘Winter Watering Trees and Shrubs.’ PlantTalk tells gardeners to water when the leaves start to fall in autumn, so plants go into winter with enough soil moisture. That makes early October the time to plan for it.
We could not confirm the video’s publish date. The guidance below comes from the PlantTalk page and CSU Extension’s fall and winter watering fact sheet, which the university marks as reviewed in August 2025.
Video: ‘Winter Watering Trees and Shrubs – Produced by Tagawa Gardens, a partner in PlantTalk Colorado,’ CSUExtension. Embedded from the creator’s YouTube channel; Colorado Local has no connection to the creator.
CSU Extension’s rules of thumb for fall and winter watering
- When: during long dry spells with no snow cover, October through March, about once or twice a month. PlantTalk’s version: if four weeks go by without snow cover, water again.
- Temperature: water only when the air is above 40 degrees and the ground is not frozen.
- Time of day: midday, so the water soaks in before a possible freeze at night.
- Trees: 10 gallons for each inch of trunk diameter, measured 6 inches above the ground. A tree with a 2-inch trunk gets 20 gallons per watering.
- Shrubs: 5 gallons twice a month for a newly planted shrub; 5 gallons a month for a small established shrub (under 3 feet tall); 18 gallons a month for a large established shrub (over 6 feet).
- Most at risk: recent transplants, evergreens and shallow-rooted trees such as lindens, birches, and Norway and silver maples. Windy sites and plants that catch reflected heat from buildings, walls and fences dry out faster.
- Lawns: the fact sheet says newly seeded or sodded lawns are especially prone to winter damage.
- Mulch: CSU notes that woody plants benefit from mulch to hold soil moisture.
- Cost: Free to watch and read.
- Details: CSU Extension fact sheet 7.211, Fall and Winter Watering and the PlantTalk Colorado fall and winter watering page.
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