Redwood Tree Problems

Over the last few years we have been getting an increasing number of people coming in with Redwood tree problems. The symptoms seem to be much the same. Over winter, usually showing up in late winter, they see a die back of 6-18” over much of the tree. Often, but not always, it is more severe on the South or West side of the tree. Usually by the time samples are brought in there are signs of regrowth starting inside most of the damage.

There are three possibilities. First is some disease attacking the trees, second is a chemical problem where the trees are picking up something in the soil or water, and last is a drought problem,

Ed Perry the Stanislaus County Urban Home and Farm Advisor has been sending samples in to Sacramento to see if they can detect a disease, so far with no success.

In areas using city water, the water quality is generally good enough that it seems unlikely to be a water quality problem. If you have affected trees and are using well water it would be a good idea to get the water quality checked. On the west side of the county, including areas west of Modesto to the San Joaquin River, there are areas of problem water. One sample I had tested showed sodium high enough to be the problem.

For most trees we have come to the preliminary conclusion that they are running out of water in the 2-3 ft depth in the summer. This can be made worse by watering to the same depth all the time and allowing salt to build up at that depth. Our recommendation, whether or not you are now having problems, is to deep water the trees once a month over the entire root area of the tree. This is not just close to the trunk but also at the drip line and beyond. It seems that drip watering also can contribute to the problem.

Redwoods are noted for being drought intolerant and salt sensitive. To grow them successfully in our climate we have to be sure to give them the best conditions. If you have additional questions or would like to report successes or failures call the nursery and talk to one of our California Certified Nursery Professionals.