Every now and then a client requests quaking aspens (Populus tremuloides) be included in their urban or suburban residential landscape design. And since I design mostly for DIY clients, I tell them I will not write in ‘aspen’ on a plan because I don’t recommend these trees for urban or suburban residential situations, but of course they are free to replace anything I recommend with whatever they want.
So why don’t I like these trees?
I DO like them. They are gorgeous in the fall—up in the mountains where there is lots of open land. They bring back fond memories of the years I spent as a ski bum in Summit County, Colorado. Ah the 70s! :-)
But I just saw an article about them in Garden Design that refreshed my mind about why they aren’t appropriate trees for suburbia. It is entitled Botanical Superlatives: The Largest Forest of One (photo here is from the article by Scottks1/Flickr). The article tells how this very stand of aspen trees in the Fishlake National Forest in southern Utah is ALL ONE ORGANISM covering more than 100 acres and aged at 80,000 years old. Yes, you see many individual trees here, but each one is a genetic clone of it’s neighbor, and they are all connected to a single massive root system under ground. Individual trees above the ground may die, but the root system lives on and produces new trees above the ground. And it continues to spread.
This—what you see in the photo above—is what you will start if you plant an aspen tree in your yard. Yes, it’s pretty. But is it being a responsible neighbor to plant something that WILL invade your neighbor’s yard? I know that evil bamboo can be contained (I personally love bamboo). I have never heard of aspen being contained. I will look in to that. If it can, perhaps that would be a good strategy.
But there are other reasons why I’m not a fan of aspen for urban or suburban use. Aspens are only pretty when they are young (my opinion). As they age, their beautiful pale bark becomes dark with fissures. And as they age, because aspen’s wood is very brittle most of them suffer at least a fair amount of breakage over time… not good if you live in a windy area like we have in the Columbia Gorge area. Aspens are are affected by a host of conditions, most notably aspen and poplar leaf spot, leaf shoot blight, and leaf rusts… all caused by fungi that love wet conditions which we have in springtime around here as they are leafing out. And just to add one more nail to the my aspen coffin, they are better suited to higher elevation than we have here on the banks of the Columbia River near Portland, OR.
If you live at lower elevation, and have an urban or suburban residential lot, I ask you to consider an alternative to quaking aspen. If it’s the trembling leaves that you love take a look at Cercidiphyllum japonicum (Katsura) — photo at right. It plays nice in the neighborhood, grows to about the same stature as does the aspen; has stronger wood than does aspen so is at least moderately wind-tolerant; has fall foliage that is yellow to apricot with touches of lavender which when crushed smells of burnt sugar.
So, please, let’s leave aspens to live wild and free in the mountains. There are plenty other types of trees that you can learn to love around your home in the city.