I don't have personal experience using Sucker Punch, but I've worked in garden centers where it and Sucker Stopper were sold. While there, I was told that these two products work on aspen suckers. Aspens are in the same genus as cottonwoods, which leads me to believe the two products would likely work on cottonwoods, as well. That said, I suggest calling the manufacturer and asking specifically about cottonwoods.

Or you could instead have the entire specimen removed because it is too close to the house anyway - cottonwoods are prone to sudden breakage in summer and therefore fundamentally unsuitable for planting sites where anything else is present that would be damaged if the tree started falling apart.

Deb C, Thanks for taking the time to answer. It sounds promising like maybe it could work without causing damage if nurseries use this type of thing.

Embothrium, I agree with you that the cottonwood is too close and also not a desirable landscape tree by any means, but I have to work with what I have for the time being. I am surprised to hear you think it might break in summer, thinking you mean when the weather isn't stormy.

woodyoak, these trees are prone to breaking, and I have it checked regularly by a tree service because it has lost a couple trunks and branches in bad weather, but they don't think there's any danger of it breaking in good weather while I'm out there. But if I hear any cracking sounds, I better be spry and move quickly!

Someday I know I may have to take it down, but there are some good things about it, the shade, the tree house feel for my second floor deck, so it's not all bad.

Most dangerous problem is spontaneous bursting apart of most of the tree on summer days. This peculiar phenomenon has nothing to do with wind.

suckers are typical for certain species of trees, it is a strategy for survival and triggered / enhanced by stress.

I can't imagine what kind of chemical could stop that without half killing a tree

----

I read somewhere about trees breaking or dropping limbs in summer due to draught which brings on changes in their cell structure and wood

hey hosta girl ....

man those are some massive roots out in the lawn ... yikes ...

suckering might also be a response to you trying to dig under that tree .. probably anywhere within 10 feet of the trunks.. and trying to grow hosta and other things ...

i too would plan on removal.. asap... the sooner the better ... or move.. lol ..

with the massive bio mass of this monster ... you gotta wonder.. how a few drops of this stuff.. is going to have much of any long term impact ... the tree is going to do.. what the tree wants to do at this point in its lfe ... and if you stop a few suckers near the trunk.. it just might pop them up.. a hundred feet away ... but then.. that will probably be the neighbors problem.. not yours.. lol ...

it is often said ... hopefully not just by me.. lol .. that a tree is twice as big underground.. as what you see above ground ... just look at your monster.. and contemplate that ...

a neighbor fell a tree like that .. i think it was his brother in law the lumberjack ... he did some fast work for me the next day ... and said when they cut it near the ground.... it geysers water a foot into the air .. wish i had seen that and got a video .... they were sober at the time ... so i presume they werent totally BSing me.. lol ...

ken

linaria, the suckers are coming from the two trunks that have come down so I imagine that was a stressor on the tree. Both times it happened from an early, heavy, wet snow in fall while the tree still had its leaves. The rest of the year it does have sprinkler water, so no drought conditions near the top of the soil, any how.

Ken, I wonder if moving might come first, but I hate to think about that! It has been a great tree to provide high shade for the hostas. I grew up where nothing grew that wasn't planted, so when we moved to a new state, I thought a tree that nature put here was great. Live and learn. My yard is full of "if I knew then, what I know now" things I would have done differently!

When we bought the house, I was told that the tree would probably die because of all the soil pushed around the base by the builder. But instead it thrived because I guess the lower half is able to put all it's roots up high enough into the lawn? I'm sure it's a monster underground and would be a fortune to cut down.

Anyone have ideas about.......This tree was four trunks, but is now two, so If I cut this tree down, won't I just have twice as many suckers coming from the base that's left and also have them springing up all along the roots in the lawn? It's too big to take out the trunks and roots below ground, right? It seems like a problem no matter what, but, for now, at least I have a big tree.