Fall and Winter Watering

A common question we have is about fall and winter water needs for landscaping. Do you need regularly water up until the day it snows? Should you water if we have a warm spell. A few points might answer some of these questions.

How much water does a tree use in the fall?

In the fall cool temperatures and deciduous trees and shrubs losing their leaves dramatically reduces the need of transpiration.  Transpiration (release of water and gases) is a normal function of the leaf.  It occurs day and night.  A plant uses 90% of the water it takes in to perform transpiration, but this reduces dramatically once the tree is entering August.

So as of Aug 1st you can reduce the watering to help the tree prepare for winter and first of September cut back again. New trees will need a bit more care if it is an unusually warm and dry fall. The tree needs to struggle a bit. This early preparation will decrease the chance of dieback from early cold snaps. Evergreens are slightly different.

Desiccation is the drying out of plant tissues.  Winter desiccation is common on the evergreen trees due to the fact that their needles stay intact through the winter. Below freezing temperatures and heavy winds can cause problems if not enough water was given before the ground froze.  The more susceptible evergreens are those with longer needles, such as a pine.  In this case it is a good idea to water your evergreens in October or November if the weather has not given enough.  Smaller shrubs can be covered with burlap to protect from the drying wind.

Even with proper watering an overly windy and cold winter will still cause desiccation.  Symptoms range from brown needle tips or in severe cases cracked stems/trunk or complete kill.   Brown needles will not harm the tree in the long run and will be expected in Montana!

**See up-coming post on how to most effectively water a tree.**