I can’t seem to find a good answer to this problem, but I think there should be a factual answer.
A year and a half ago I bought a house in Northwest Montana adjacent to Flathead Lake. We love the house, but it came with 6 mature Poplar trees, some of which were planted in the middle of the front and side lawns. When we bought the house we knew that some of the trees were struggling, but nobody I talked to then knew what to do about it.
Within 12 months 2 of the trees had died and 3 others were looking poorly. I called a tree guy to come over and take down the 2 dead trees and he told me the other 3 weren’t long for the world. He was right, and we now have one healthy Poplar tree left. I’m actually okay about it since the trees provided zero shade and shed thousands of leaves I had to deal with.
When the dead and dying trees were removed I had their stumps ground down thinking that would be the end of it, but boy was I wrong. These trees had large shallow roots, some of which had broken through the lawn, which made mowing a challenge. This summer I’ve noticed dozens of leaf covered suckers coming up through the lawn every week. These suckers seem to pop up overnight and grow extremely fast. I try to cut them off as soon as I see them, but it’s a losing battle.
I get that the roots are trying to sprout leaves that will provide them with the sugars they need, but I don’t want them to grow and I can’t dig them out without destroying the lawn and starting over. Is there some way to stop these roots from sending up suckers without poisoning the entire lawn at the same time?
The roots/suckers need the trunk in order to survive. A few recommendations I found online are to chop the root with an ax, to separate it from the trunk, or to kill the trunk by drilling several holes in it and filling them with salt. When the trunk is dead, it will be (according to the web) easy to chop up and discard (and the roots/suckers will die).
I’d never heard of a tree doing this before. Fascinating!
I had typed out a long anecdote about grinding stumps and then re-read the OP and realized they had already done this, so I deleted the post.
About all I can add is if the roots are shallow enough, they can be ground down as well, but if they are sprawling throughout the yard that may be more of a pain then it’s worth.
Just saw @Riemann recommend stump out, that will work as well. Make sure you get the right stuff, as the other kind you can get only works on dead stumps or roots.
I should have mentioned that after the stumps were ground I filled the stump holes with soil and planted grass and that seems to have worked as far as the stumps are concerned, but the meandering roots are where the shoots are coming from and they are everywhere.
“The roots/suckers need the trunk in order to survive.” That doesn’t seem to be the case since the stumps are gone yet the roots continue to sprout suckers.
If Triclopyr worked on roots that sounds like that would be the best thing since it doesn’t kill grass, but since I live adjacent to a wetlands I can’t risk getting it into the waterways and killing the fish and other wildlife in the area.
No sure how big the area is, but I have successfully smothered out leftover roots by covering the whole area with professional landscape fabric. After covering the area with landscape fabric, I secured it to the ground with landscape staples, then I poured a few bags of topsoil over it and seeded with grass. It takes about 1-2 years, but the leftover roots self compost.
Adding to Nayna’s post which mentions drilling holes in the trunk & filling with salt. My information specifies Epsom salt. Maybe regular salt works too, I don’t know. I used Epsom on a Willow trunk. It works but it takes awhile. For the first year I had sprouts. No longer. And by the looks of things it could take years for the trunk to deteriorate. In my situation I don’t care, but something to keep in mind.
Incidentally if you do this, cover the trunk after filling drilled holes to keep sun & rain off it. But dampen the salt to activate before covering. It crossed my mind that depriving the trunk of nourishment in itself could be what works, but Epsom salt is cheap . . .
Here’s what I learned from an old man, in a bar. Cut the tree as close as possible to the ground. Use a regular drill to drill some (reg size) holes into the top. Bigger around tree trunk, more holes. Using a teaspoon dribble gasoline into the little holes. Do it two or three times on the day you cut the tree. That’s it. That’s everything.
Sounded too good to be true, too easy, but I had gas for my mower so I tried it. And have used this method repeatedly to kill everything from 2’ diameter trunk trees, to fleshy stalked persistent weeds. Works an absolute charm.
Weeds will wither and die never to return, trees stumps etc, by next season you’ll be able to pull out in big chunks till nothing remains.
My neighbour next door had his fence replaced, in part because self planted trees had undermined it and grown quite large, 12” across and bigger. I told the fencer I could kill them, and I did. They built the fence right over the stumps, in places, they had no choice really! Not so much as a sprig, shoot, or leaf has come out of those stumps, and it’s been three plus years!
I used Roundup (glyphosate) to kill a hackberry stump in our backyard. (Hackberries are notoriously hard to kill).
What I did was drill a bunch of 5-6" deep vertical holes in the stump, and basically just poured the Roundup in, so that it wasn’t spreading around the yard, but it was definitely getting into the stump’s circulatory system.
Yup, straight undiluted Roundup. We’ve done away with notoriously hard to kill oleanders, olives and African Sumac by pouring just a bit of Roundup on the stump after we’ve notched it.
Assuming you mow the suckers down every week or so, I would expect that the root system is fighting a losing battle, expending more energy putting up the suckers then they are returning in photosynthesis. Of course, the war of attrition may take longer then you’d like and the aesthetics in the meantime may bother you.