Kate, you first ask how to maintain aspens, but I think what you're after is how to get rid of them. Am I on the right track?

In any case, there's no easy solution. If the mother tree is cut down, a huge explosion of "suckers", which in this case refers to sprouts from the root system, will develop. You will be able to use a broadleaf herbicide-like the kind of thing used to kill dandelions in lawns, but it may be a long battle.

If you do not wish to remove the mother tree, then your options are more limited still. You could use a "burn-down" herbicide like diquat or some of the soap-based products like "Sharpshooter", but this will be very tedious and any overspray into the surrounding lawn will cause at the very least, a small patch of burned-looking grass.

Why don't you clarify just a bit and we'll see what we can come up with.

_+om

So it's a little bit of both. I've included a photo. But we like the existing mature trees and don't want to do anything that might kill them. But down below are all of the large suckers/small trees. Not sure what to call them. A little hard to see in winter, but when there are leaves, it looks very messy and unkept. I'd like to clear out most of the suckers and plant a few fir trees (which I know might eventually push out some Aspen, but I'm ok with that in 10-20 years). Does that clear it up at all? Basically, how can I remove all of the little trees (none of the big) without hurting the big ones or somehow causing even more suckers to pop up. To my knowledge, the main tree is still thriving, but I'm not actually sure which tree was first since we just moved in.

Well, one thing that nature does all the time in aspen stands is, as the aspens mature-they don't live very long in tree terms-conifers such as spruce and fir get established in the light shade of the stand and eventually, as the aspen dies out, the evergreens become the dominant trees in the stand. Maybe that pertains to your situation somehow. So I guess you're not talking about something happening in a lawn, right? If so, I'd go ahead and interplant the firs you want, where you want them, and just keep the aspens clear enough to allow these fir trees to get going. the least you do to them, the fewer new suckers you will have. Are we getting closer?

+oM

I think we are getting close! Thanks for your input! Would you suggest chopping the suckers down at the base, or trying to dig them up? I guess I worry digging will instigate more to pop up, but that's not based on anything!

And yes, my thought is to plant some firs that will eventually push out old/dying aspen so that we're never left with a bare spot there. We have many mature spruce on the property that all have the same needle disease and sadly will all have to go.

Don't try to dig aspen roots up, they are connected and you will harm the remaining trees. Just cut the suckers at the base.

these are trees that grow as a copse ... see link

link

as far as i understand ... in theory ... they are all one tree ... its how they grow.. its genetic ...

if i am correct .. rather than befuddled ... you either want them ... or you dont ..

you cant really selectively thin this type of tree ... or change its genetics.. thru pruning ...

well .. you can ... but every year.. you are going to be out there .... taking your valuable time.. thinning etc ...

get a few of the replacements planted ... established.. and thriving.. and then completely destroy the plant you dont want ... cut them to the ground.. and then apply a stump killer or 100% round up .. or the cheaper generic ... use the very expensive applicator.. found at this link.. to apply the undiluted product to the cambian layer of the cut:

this allows minimal usage and perfects application where it need be

hey.. we can do more than one link in a post ...!!!

when it all boils down ... aspen is a wild tree... that takes over vast areas in the wilderness ... it is not really a backyard friendly tree ... its probably one of the reason the nut who planted it.. decided to move... lol

think about the fact... that these pix.. could all be one tree ... a bit of a whimsical idea ... but should cement the concept i am trying to relay

ken

i highly doubt .... this could be done w/o a chemical killer.. except with a lot of back breaking labor ... and all the power to ya.. if you want to go at it that way ..

again ... you can not change the genetic predisposition of a plant thru pruning ... perhaps the exception would be bonsai ....

ken

Hi again, Kate. Glad we're getting somewhere! Ken mentions cut-stump treatment with herbicide, and yes, you could do that. But I don't think you want to because one of your priorities is to always have "something" there. What's more, if this clonal grove of aspen is like most, it could really run into some pretty big dollars to treat the entire thing. No, I would mimic nature, as I described above, and just get some of your chosen fir trees going in the area you want them. And do no more to the aspen than necessary, just cutting away the very stems which interfere with the new trees' getting enough light/space/etc. In fact, depending on what species of fir you go with, you might not have to do anything beyond planting them. All across the northern tier states can be found balsam fir, growing in precisely the situation I describe. And that tree has considerable shade tolerance-the most of any common evergreen so far as I'm aware (yes, more so than hemlock). So what fir species were you thinking about?

+oM

edited to add: For some reason, I thought you were in NY state. Now looking back, I don't see your location. That tidbit would help too, although the process I describe goes on pretty much wherever early-succession trees like aspen are later replaced by fir/spruce.

Thanks everyone for your insight! (FYI Ken- We are in the Detroit area, but moved from Madison, which based on your username is of note to you!) I think we'll try our hand at chopping some of it down and see how it does. We'll also be planting some conifers near the base and hope that over time they do as nature intends and push out the Aspen. But I will say, as we look around our property, we see other mature Aspen all around. Some in our yard, some in others. I know a grove can be massive, and I do fear that all of the Aspen we see are connected. I think the main/first one is one that was pictured and in our yard. I do like the trees, but certainly would not plant them myself, especially if I didn't have acres to work with (which we don't).

Depending what kind of Aspen you have - both trembling aspen and large tooth generally live 80 to 110 years, relatively short in the tree world. Lombardy poplars typically live only 25 to 30 years, but I don't think they would reach the size you have.

Applying any kind of pesticide is a bad idea, since the roots are interconnected, and poisoning some will kill others. One of THE ways aspen and poplars regenerate is thru root suckering, so the only two ways of minimizing more growth is to cut them off every year, or shade them out. Poplars are one of the first species to infill after a burn or cut, so they are geared to grow.

I personally like Trembling aspen, and other poplars and have planted many. Except for branches dying and falling off (same problem with most trees) not really any problem with them.

Once the suckers are cut down will a riding mower and weed eater combo keep them in check through normal regular use?

yes. regular is key word, and eventually some suckers will give up, but others will likely replace them