Seasonal observations of the UCCE Master Gardeners
- Author: Kathy Thomas-Rico
Published on: September 2, 2011
What’s going on with the white birches? Seems as if an awful lot of them are dying. From my front window, I can count three, good-sized DEAD European white birches (Betula pendula). Their leafless, bone-white branches stand in stark contrast to the seemingly healthy hackberries and redwoods and oaks around them.
Alas, this is old news. White birches have been dying off during our hot summers for a long as we have persisted in planting them here. White birches are lovely, and popular in our area. But, they come with a list of issues of which we all should be aware:
- European white birches are native to, well, Europe. Specifically northern Europe, where there are cooler climes and plenty of rainfall to sustain the trees. They grow magnificently there, and to their full potential, much larger than any you’ll see in Solano County.
- When birches get stressed during our Northern California summer droughts, borers move in. The bronze birch borer, Agrilus anxius, is the main culprit. Apparently there is quite a large local population of the borers. Intensive insecticide applications will keep them at bay. Check the University of California Statewide Integrated Pest Management website for more information: http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/birch.html
- Birches are thirsty trees. And the amount of irrigation must grow with the tree. Often, birches — as well as other thirsty trees, such as alders and maples — thrive in well-irrigated lawns areas.
- Even in the best growing situations and climate, birches are not long-lived. You’d be lucky get 30-40 years from a European white birch.
A dead European white birch stands in stark contrast to the healthy landscape around it in this Vacaville yard. (Photo by Kathy Thomas-Rico)
A row of older white birches thrives in a well-irrigated strip of turf along West Monte Vista Avenue in Vacaville. (Photo by Kathy Thomas-Rico)
Tags: Agrilus anxius (1), Betula pendula (1), Birch (1), bronze birch borer (1), European white birch (2), Integrated Pest Management (1), IPM (3)
Comments: 3
Comments:
by Sharon Leos
on September 2, 2011 at 9:24 AM
We had a birch tree in our well irrigated front lawn for fifteen years. I write had because this summer it died! Perfect timing of your article, we'll look for signs of borers when we take it down. Now we know it may have just lived out its life. Thanks!
by Donna J. Seslar
on September 2, 2011 at 7:33 PM
Great, interesting blog! One of our neighbors has a house set back from the street and they have planted white birches as well as other trees in what amounts to mini forest..all trees seem to be thriving. As another neighbor teased, ""pretty soon I will be able to hunt moose in there!"
by Carolyn Neumann
on September 2, 2011 at 7:54 PM
As with any unhealthy tree, they become a breeding ground for insect, fungal and bacterial infections. Keep your lawn trees healthy by fertilizing and assuring they get enough water but removing lawn or anything growing under them that competes with their water and food. In a perfect situation the diameter of the circle under the tree should be as wide as the drip line. Most people however want grass under them in which case they must be pampered even more. Pamper your trees and keep them healthy.
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