On a trip today to Trout Lake, we observed many weeping willows looking seriously blighted on both sides of the lake. A similar blight seems to have affected a curly willow in our yard. Leaves blacken, curl up and die. The stems look as if burnt.
I googled "willow blight" to read more about this disease, and apparently it has been moving steadily from the East Coast for decades, and had been observed in Vancouver as early as the late 1970s. It's fungal - actually, a combination of two fungi - and there really is no treatment, as the fungus hides inside the tree. According to one article, the blight flourishes during wet summers, and not only rain but also mist or fog can worsen it. Planting trees too close together also helps it spread.
Trout lake has a great many willows that add a lot to its beauty - I'm sad to see that we may be losing so many. The large willows that are farther away from the lake and on higher ground seemed to be healthy, but most of the trees that are closer, and close to the other undergrowth, are not. The new growth on the recently constructed willow fence looks fine, so far.
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Once the excessive spring rains finally gave over to summer dryness, the willows put out a normal or better complement of healthy leaves, though you can still see the blighted ends. Apparently willow blight can be a chronic rather than a terminal disease.
ReplyDeleteThanks so much for this post-- it helped me bunches on my biology paper! :)
ReplyDeleteDoes anyone know who constructed the willow fence?
ReplyDeleteThe trees look really terrible today (May 2014). We thought it appeared that all the willows in the park were affected. Are we going to lose them?
ReplyDelete