Birch trees are highly-susceptible to the dreaded Bronze Birch Borer – this is a type of insect that attacks the upper canopy of birch trees. You’ve likely noticed birch trees with dead upper canopies – that’s the telltale sign of an impacted Birch tree.
Seattle birch trees in particular are at risk – we see this constantly as a local Seattle tree service that specializes in Tree Healthcare.
As a result, we have created a quick guide to how you can help your Birch tree survive & thrive!
My birch upper canopy is dying out — now what?
Okay, don’t panic. By moving quickly, we may be able to help the tree out.
First, how much of the canopy is dead? If it’s still less than 20-30%, we may have a chance. Once a tree has lost more than 20-30% of its canopy, it’s unlikely to recover – it just doesn’t have the foliage needed to keep generating energy for it to survive.
But if it’s less than 20-30%, call an ISA-Certified Arborist right away (shameless plug for ourselves here, we do this kind of work all day!). They should be able to prune away the dead portions of the canopy right away. It’s important to prune away the dead canopy so that the insects don’t spread to the live portions.
That kind of pruning work can be done year-round, it may just be tough at times to tell how much is dead in the winter. So you may need to do one round of pruning in the winter to get ahead of the issue, but then follow up with more pruning if new dead spots appear as the tree goes through the growing season.
Can I treat my birch trees with insecticide?
Yes! At Blooma Tree, we employ a microinjection treatment (no crazy sprays) that goes directly into the base of the tree. The tree then pulls the insecticide up to the upper canopy through a process called transpiration.
In order to be effective, we have time these treatments to the seasons during which Birch trees are actually transpiring, which is when the tree is in full leaf-out.
As a result, May is when we start doing treatments, and we usually stop by October, depending on when the trees start to go dormant, which is weather-dependent. So no, September is not too late to treat your birch tree for the season. But December might be.
The actual treatment is effective for two years. It’s not a silver bullet — it’s meant to give the tree a fighting chance. In order to be truly effective, it’s crucial to support the tree with good watering practices & soil amendments. The Bronze Birch Borer goes after stressed trees, particularly drought-stressed trees. Also, the tree needs plenty of water to effectively transpire the insecticide to the upper canopy.
In fact, if we see your tree looking too parched, we’ll recommend you water it first well, and then we’ll come back a week or two later to do the injections so that they’re actually effective. We want to help you save your Birch trees, not just sell you a service.
Conclusion
Yes, you can save your Birch tree. No, there are no guarantees – but we can help you give your tree a fighting chance.
Importantly – we recommend getting the microinjections done BEFORE you see signs of the Bronze Birch Borer. It’s much easier to do preventative care than trying to deal with the insect once infested. Let’s work together to keep your Birch trees healthy so that they aren’t a target in the first place.
