Water critical for trees in winter
By John Forshee
River Valley District Director/Horticulture
Winter has been relatively mild so far and although I appreciate not having to scoop snow and being able to run errands without my coat in the afternoons, our landscape plants may be paying a price. The snowfall that we have had has been welcome, but it has done little to diminish the drought conditions that we are facing.
The Kansas Weather Data Library shows that the River Valley District was anywhere from 4.5 inches to 8.5 inches below normal precipitation through the first nine months of 2012. We all know that the fall and early winter has not brought an abundance of moisture and so as winter continues into spring we need to keep the care of our trees and landscape plants in mind.
Water is the single most critical factor to the survival and steady growth of trees. The dry winter and spring of 2012 was followed by a hot and dry summer. As a result we saw many of our trees exhibit premature leaf drop, undersized leaves, curling of leaves, wilting, and branch die back. These conditions often result in secondary problems like disease and insects attacking the tree. Over time the cumulative effect of these conditions can be tree death.
What can we do? Well, since water is the single most critical factor, then water becomes our number one answer. As difficult as it might be to drag those hoses out, if winter conditions allow, then trees and other landscape plants should be watered.
What are the conditions? The biggest factor is that the ground should not be frozen in order that the water will soak in. What we don't want to do is to apply a layer of water that does not soak in and subsequently freezes and forms an ice layer. Just like overwatering, this ice layer can prevent oxygen from reaching the roots in the soil and result in plant damage. Watch the weather for that balmy period we often get when the days are warm and the night temperature stays above freezing for several days. You will notice the frost start to come out of the ground and the streets might be damp in the morning like it rained overnight. That is the ideal time to water your trees and other landscape plants in winter.
For trees, soak the upper 12 to 15 inches of soil, running the water slow and allowing it to soak in. Kansas Forester Bob Atchison recommends applying two gallons of water for every one inch of tree diameter, spreading the water over the entire root area.
We might be tempted to fertilize and prune stressed trees but that might be counterproductive and cause stressed trees to expend energy they shouldn't. Save that routine pruning and fertilizing for a time when conditions allow the tree to better handle the stress.