|This spring we purchased 12 white spruce trees to form a hedge. Within one week three of the trees turned paleand needles started to drop. I spoke with the nursery the plants were purchased from and they agreed that it was a watering problem that had happened while under their care. We had a very dry spring. All season we were very diligent about watering the remaining trees, but now I see signs of browing on the inside of some of the trees. The needles on the outside are still healthy and dark green. This is a very different look from the three dry trees of early spring. My question is- could we be overwatering them? What are the signs of overwatering vs. underwatering. Thanks for any help you can share with us.|
|It is possible that what you are seeing now is normal because spruces will drop some of their oldest needles each fall.
On the other hand, since these are newly planted trees and there have been some stress problems, I would suggest you consult with your county extension to make sure there is nothing else going on because there are various insects and diseases that can cause needle drop.
In terms of watering, your goal is to keep the soil evenly moist but not sopping wet. Using several inches of organic mulch over the root zone (but not touching the trunk) and applying water as a slow deep soaking will help maintain that soil moisture down deep where the roots are. (A daily light sprinkling usually will not.)
The only way to tell how effective your watering is (or isn't) is to water, wait several hours, then dig down into the soil and see. To judge when to water again, check the soil with your finger. When the top inch or so has dried, water again. In the fall, as the weather cools and there is more natural rainfall we usually need to water less and less because the soil stays moister longer on its own. Keep checking though up until the soil freezes.
Good luck with your trees!