Let's unpack that starting with the different varieties of Aspen, because I would think an Aspen is an Aspen. What makes it difficult to know if the one that you buy at the store will thrive once you plant it?
"So in some sense, an Aspen is an Aspen. Uh, it's, uh, a really widely distributed species. And so in fact, the most widely distributed species of tree in North America, and it grows from Alaska all the way to the East coast of North America and Labrador all the way into Mexico. And the only places it's absent in North America is really the Southeast United States and Oklahoma and Kansas.
And so you would think, well, gosh, this thing grows anywhere. It should grow really well in my yard, because my yard is also anywhere. But, uh, in order to grow in such a wide range of places, aspen has a lot of genetic diversity. And so you need to have a genetic match, essentially, for your soil type and your conditions. And if you don't know where the aspen came from, what it's programmed to do genetically, then it may or may not do well in your site. And a lot of trees don't do well along the Front Range. It's too hot, the soil is a little too heavy, and so they just tend not to thrive."
How likely would an aspen tree from the mountains be to thrive in a neighborhood along the Front Range?
"So, uh, aspen tree from our local mountains is probably I'm guessing probably among your worst options because the growing conditions at high elevations in Colorado are substantially different from the growing conditions at low elevation, predominantly in soil texture and soil pH, but also in terms of water relations and climate conditions. But if I were going to pick an Aspen that I thought might do well in my yard, I think I'd be looking for a tree. Maybe from Nebraska that's growing at a lower level with a little bit heavier soil. Than one that's growing up in the decomposed granite, you know, in the Rockies, because that's really different than what we have here on the front range."
John, one of the fascinating things about Aspen is that so much of an Aspen as an organism lives underground in these complex root systems. A single Aspen tree can very quickly turn into a grove. What kinds of challenges does that present for a homeowner?
"Well, that is the primary challenge, I think, for homeowners hoping to plant a tree, because an aspen is not a tree. An aspen, as an organism, wants to be a grove of trees. It wants to make multiple trunks and an extensive root system as a way to make sure that it persists over time. Individual aspen trunks, as far as trees go, don't last all that long, but aspen organisms do. Can last a long time back. The oldest and largest one in Western North America is something like 17 acres in size. And I think it's at least a million years old."
Whoa. And that's a system. So the root system is connected.
"That's that's one plant. So the half joke that we will often use in extension is if you're going to plant yourself an Aspen tree, you are planting your neighborhood and Aspen tree starting with your immediate neighbors, because that tree is going to show up in everybody's yard as it grows. Follows its natural development to make a grove of stems."
Oh, sounds like you should go to your neighbors and just let them know what you're up to. How long does that take? How quickly can I go from having a single Aspen to having a full grove?
"Aspen trees will do that relatively quickly. You will start seeing those root shoots, often called suckers, coming up from the root system almost as soon as the tree is established.
So within just a few years of planting that tree, you can have new shoots showing up nearby. Usually within 30 feet, but I think the farthest that I've seen recorded is up to 100 feet away, and they're going to be sending up these new shoots to, uh, to join in the fun."
Okay. How much of a hassle are those other shoots that sprout up in the yard?
"To an extent, it's a matter of perspective. But one of the calls we get is, you know, I've got these things in my, in my lawn. What do I do with these? You will have people who don't realize that they're connected to the trees, and so they'll treat them with herbicides. That, of course, can be damaging to the entire tree and even make the problem worse. You have people, you can mow them, they try to dig them out. All of those can be damaging. Mowing those eventually makes sort of a twiggy bundle of daggers in the lawn, which is not great for walking barefoot out in the grass."
No, not ideal.
"Right."
I have also heard the leaves are toxic for your lawn. How true is that?
"The leaves are not in themselves toxic to the lawn. Um, Leaves of any tree, including aspens, can smother a lawn if you don't break them up or don't pick them up. Trees tend to compete with the lawn though, and so that's where you'll have a lawn not do well under trees is because of competing for light and water.
Now, if your heart is absolutely set on planting an aspen, John says you can increase your odds for success. You can look to a local garden center that knows which types of aspen might thrive in your neighborhood you And the origin of the Aspen trees they sell, or you can look for help from neighbors who have had luck growing their own Aspen tree.
"One of the things that always surprises me driving around town is you will come across glorious Aspen trees. That somehow beyond all odds have just thrived in that situation. And so again, if I were hoping to make a successful Aspen attempt, I would, uh, introduce myself and make friends with whomever had that beautiful Aspen and then think about maybe propagating it from one of those root suckers that's coming up and getting a tree that you know is performing well locally, provided that the soil in your new friend's yard is similar to the soil in your yard."
Okay.
"The list of trees and shrubs that do well here and are glorious is long, but sadly, none of them, none of them are aspens. And so, you know, for that white bark, yellow color, twinkling leaves, uh, there's, there's no tree that can replace it. And that's why it's one that we get questions on because people just love it and want it."
