Winter Watering Evergreen Trees and Shrubs During Dry Periods
Many locations across Montana have had a dry few weeks and currently don't have very much snow cover. If you live in an area that has had warm daytime temperatures in the high 40s and low 50s, with minimal/no snow cover and little to no precipitation over the past few weeks: it may be beneficial to water your sensitive trees and shrubs this week before temperatures drop again.
Trees and shrubs located in windy areas, unprotected locations, and with south-west exposures can be especially susceptible to winter-related drought injury. Winter watering of trees and shrubs is a useful practice in arid/semi-arid climates, especially during warm and dry winter periods. Making sure that trees are not water-stressed during these warm periods can make the difference between your trees getting a healthy start in the spring or struggling to thrive during the following growing season. This is especially important for evergreen trees and shrubs (since they are losing moisture all winter long), and can reduce winter injury and desiccation the following spring. Younger and newly planted trees and shrubs experience much more water-stress than established ones (due to their restricted root systems), and special care should be taken to ensure that they get enough water during these dry periods.
 Tree showing symptoms of evergreen winter injury (Photo: Eva Grimme) |
Water your evergreen trees and shrubs during warm winter months if you have no snow cover and have had minimal/no precipitation. Take a hose or bucket out mid-day on sunny days when temperatures are above 40? F. Water slowly, letting it soak into the soil, and not puddle on top. Don't just water at the base, instead aim for the dripline and surrounding area to ensure water is getting to the critical root zone. A rule of thumb for watering trees is to provide 10 gallons of water per inch of trunk diameter per month. Adding a 3-4 inch layer of mulch (like arborist wood chips) can also help with conserving soil moisture.
For more information on caring for your landscape plants, contact your local MSU Extension Office.
Check out this publication for more information on winter watering:
https://extension.colostate.edu/topic-areas/yard-garden/fall-and-winter-watering-7-211/
Abiya (Abi) Saeed
Extension Horticulture Specialist
[email protected]