It sometimes surprises people, but trees and shrubs benefit from winter watering during dry years. This is a good time to pull out the hose and give them a deep drink.

Don’t hate me. I realize much of the country has experienced a winter like one they haven’t seen for many years, if not decades. I admit it: We in Montana might be giggling a little bit, especially since we enjoyed a few days of record-breaking temperatures, reaching 70° when it was snowing near Myrtle Beach. But we also understand our mirth is short-lived.

The other implication of our unseasonably pleasant weather is significant drought. It was a dry autumn, and, despite a fairly early snowstorm, we are still over 20 inches below the normal snowfall.

Winter Watering of Evergreen Trees and Shrubs

Trees are Physiologically Active

Even in the winter, trees don’t shut down their entire system. When soil temperature rises above 28°, they can still take up water. It’s more likely for trees to die of dehydration in winter, when warm spells occur without available moisture.

This is particularly important for conifers because they don’t lose their “leaves,” namely their needles. Water transpires throughout the year, even in winter, especially when it is windy, making it imperative to replenish it when the weather cooperates.

There have been many reports across the region of trees showing signs of budding due to our extended mild spell. Triggered by warm temperatures, hormones within the trees’ systems de-harden the bud shell, shifting the tree’s physiology from dormancy to growth. While this is concerning on several levels, because if typical winter weather returns, they will be damaged. When the tree is active and no water is available, it adds another layer of stress.

When is Winter Watering Best Done?

In semi-arid regions, or places where you just are experiencing a drought period, try to water your trees and shrubs once or twice a month, if the weather allows. You need a time period when the ground is not completely frozen, and daytime temperatures are above 40°. Also, don’t water if you’re on the precipice of a significant weather change, especially deep cold. Here in Montana, we are known to have days of 40, 50, or even 60° weather during the winter, only to have it plummet to single digits or even below zero the next day. That does not help the trees at all because the water is not available. A few days of nice weather after the watering allow the tree to utilize the available moisture.

How to Winter Water

The goal of winter watering is to provide moisture to the feeder roots, which are found closer to the edges of the canopy. Ideally, you would set up a drip hose 6 to 8 inches inside the outer line where the canopy falls. This way, you provide water to those smaller roots that will bring it into the tree’s system. Do not put the hose near the trunk of the tree because that is not where the viable roots live.

An ideal watering method is a slow drip over a couple of hours with the irrigation hose. But, if you do not want to drag out your drip hoses, you can just use the regular hose and provide 10 gallons per inch of the tree. If it is a three-inch tree, plan on 30 gallons. It’s also preferable to spread watering around the tree’s perimeter. So allow it to water for a few minutes and then move it to another location along the drip line.

Historic Drought

As we all know, the weather doesn’t stay the same for long, but if you are in a dry spell, take advantage of a couple of nice days to do a little winter watering. Your trees and shrubs will thank you for it.