Over the past few years, we’ve seen quite a few Birch trees around Seattle die. Usually, the top of the tree will die first, and before you know it, the whole tree looks like it’s in decline. We have pruned, removed, and treated dozens of Birch trees in the greater Seattle area. We walked our own neighborhood in north Seattle and saw 16 birch trees. Of those, 4 birches were healthy, 6 showed signs of an ailing tree, and 3 were dead.
What is the problem?
In a word: Bronze Birch Borer
The Bronze Birch Borer is a nasty insect native to eastern Washington. Because we are planting birch trees as ornamentals, the borer has a feast right in our yards. For detailed info about this pest, click here. How can you tell if your birch tree has been hit with the bronze birch borer? A quick look at the top of your birch tree will clue you in. Look at the photos below, taken in a north Seattle neighborhood, to determine whether or not your birch tree is healthy or if it is infested.
There are 4 ways you can help save your beautiful Birch trees. Two help create a strong tree that can better resist this pest, and two tell you how to attack the beast.
1. Deeply water your Birches at least once per month in dry weather.
The past few summers have been dryer and hotter than normal in western Washington, especially July – early September. During these hot, dry months, remember to give your trees a deep soaking. If the water just runs off, try using a soaker hose or applying mulch.
2. Mulch around the roots.
Mulch is a wonderful material for keeping soil moist, preventing weeds, and feeding the soil. Arborists’ wood chips are the best material, but processed mulch works, too. Apply it twice a year, 3-4″ deep, keeing it away from the touching the base of the tree, like these illustrations show:
3. Remove the deadwood, using proper pruning cuts.
If your birch is on the small side, you can do the pruning yourself. Be sure to learn how to prune correctly, or you might do more damage than good. An excellent website for learning how to prune is here.
If your birch is taller, you need to hire professionals (like the Blooma Tree Experts!). We remove all the deadwood in a birch tree, thus giving it a better shot at survival.
4. Have a professional apply pesticide.
For birch trees that are infest with the borer, you must have the tree treated with a pesticide if you want your tree to survive. Our method involves inserting “pills” of pesticide into the tree. This is nice because there is no chance of overspray or pesticide on the ground, so your pets and children are safe.
Unfortunately, if your Birch tree shows 30%+ dead, it is unlikely to recover and should be removed. As always, we do provide free bids for all tree services, including birch treatment or removal. Call Blooma at (206) 714-9835 for a free bid in the greater Seattle area.