People were pointing and actually laughing at us as they pulled off I-80 when we fired-up the irrigation system for the nursery and landscape this Friday (1/5). Their loss I guess. We have been fielding calls every day, usually prefaced by "...this might be a stupid question but..." at which point I often interrupt and say "Yes, you should water" (...as though I could read minds). In our Planting Instructions and Winterizing hand-outs, we say: "Maple, Birch and Alder are particularly susceptible to drought injury in late fall and winter. Always send your garden into winter with moist soil. The last watering is often around Thanksgiving. Even dormant trees need water, so... if we have no substantial rain or snow, water at least once a month, even through the winter." Your plants are sleeping, they're not dead.
In sunny locations if the snow is gone, trees and shrubs planted within the last 2 years, small plants, young plants and groundcovers need to be watered. We have been watering the sunny south-facing slopes in the nursery since we had that little rain last week. I watered the sunniest parts of my exposed lawn earlier this week. Think "light rain" when watering. You want to avoid saturating frozen soil and creating a solid ice layer that will suffocate roots and beneficial soil microbes but all those same components of soil need some moisture to survive. Water only during the warmest part of the day (when temps are over 40°F) and give the water a chance to soak well in before afternoon shade and cooling sets in.
This is a year when we are glad we promote antitranspirant applications and plenty of mulch.
Colorado State University has a handout on the subject and we are pretty much in agreement with what they say: look here.
The temperatures turned dramatically cold this fall before many plants had a chance to naturally shut-down (many still have leaves on them). These would be more susceptible to winter die-back in a NORMAL winter. I am already seeing damage to some evergreens (Cedar and Giant Sequoia) and broadleaf evergreens (Holly, Oregon Grape and Manzanita). It will be yet another instructive winter seeing what really THRIVES in our always challenging climate... stay tuned.
Sat, January 7, 2012
by Eric Larusson