One of the most common and beautiful trees homeowners plant in their yards is the Blue spruce,
so named because of its blue-green needles. These trees also have a lovely pyramidal shape, have
dense foliage, and are easy to care for.
Unfortunately, they seem to be dying off. You won't notice it unless you stop to periodically
examine the health of these trees. The decline started gradually several years ago around here (New England),
with only a few trees being affected. This year I've noticed that nearly every Blue Spruce is in
serious decline.
Here are the symptoms:
- The lower half of the tree shows the vast majority of decline.
- The branches on the lower half of the tree begin to "pancake", collapsing onto lower branches. This leaves "holes" in the normally dense foliage.
- The very symmetrical look of the tree is altered by occasional branches sticking out further than usual.
- Needles, especially on smaller inner branches, turn brown and fall off. If there is snow on the ground, you can often see its surface covered with dead needles. If there is no snow, try shaking a branch - you will likely see needles fall like rain.
- Needles on the branches about a foot from the tip begin to take on a slight yellow-brown tinge.
- Where you could never see the trunk of the tree before due to foliage density, the trunk now begins to be easily visible as bare branches become more common.
- As all these symptoms progress, the beautiful blue-green color of the branch tips fades, and you find yourself wondering if this is really a "blue" spruce!
As you can see, the progression of this disease causes Blue Spruce trees to lose all the attributes that homeowners love about this tree. Along with this may come the temptation to cut the tree down.
A few other notes:
- Younger trees (under 15 feet tall) seem to resist this decline better than more mature trees.
- As my research shows (see the information on Blue Spruce), the likely cause of this decline is White Canker. Strangely, however, while a key indicator of White Canker is bark splitting, spruce trees having White Canker show no evidence of bark splitting.
- Since I have no Blue Spruce trees in my yard, I'm unable to tell if the fungicides that are effective against White Canker will have an effect on Blue Spruce trees.
- While I have yet to see a Blue Spruce that has died from this disease, I have seen a few that are about 30% defoliated, and, if anything, the decline seems to be accelerating. At this rate, I expect to see 90% defoliation within about 4 years.
So the next time you pass by a Blue Spruce tree, check it out and see if you find any of the disease symptoms listed above.
Post your observations here. Oh, and be sure to note what part of the country you are from.Don Peters
Moderator
