Have you tried a weedwhacker?

"Weedwhacker won’t do squat to kill them indefinately (sic) or prevent recurrence."

And neither will dabbing them with herbicide!! They are root suckers and any tree in the Populus genus will produce them.....in abundance. They can form large, continuous colonies that can cover acres if left alone. The only way to get rid of them permanently is to have the parent trees removed and the stumps ground. And even then you will have suckers popping up indefinitely until the root system finally dies off.

A weed whacker/string trimmer is the most efficient way of dealing with the suckers that pop up in your lawn until the larger problem - the poplar trees themselves - can be addressed.

^^^You have completely missed the point! The herbicide might well kill off any suckers it's applied to. The problem is more will continue to appear. That is just the nature of these kinds of trees. You would need to apply herbicide by the bucketful to kill off the originating tree source so the best one could hope for with this method is a temporary reduction in existing suckers, only to be followed by more and more new suckers. Ergo, herbicide really doesn't do squat either!

And since you need to cut the suckers back to apply the herbicide for it to have any effect, why not just whack them off at ground level to begin with and not worry later what's to be done with all the half dead suckers poking up and defacing the lawn? Since they are all attached to/emanate from much larger tree roots, even if dead, they will not be able to be pulled up.

btw, if the weedwhacker is powerful enough to handle mature weeds, brambles and brush, then it can easily address some skinny root suckers!

I wage the same battle with aspen suckers, though the riding mower does a good job of buzzing them off. The balsam poplar I've needed to resort to girdling and chemical treating that they and as many of their suckers die, balsam suckers were pushing up through badly damaging my asphalt driveway, nasty things!!

I planted a small populus grandidentata in my yard. It didn't make it. I'm so glad it died.

The suckers come up from, and attached to, established roots. That's why they're hard to pull.

I have treated choke cherry and quaking aspen suckers with half strength 24D chemical and that has been semi effective for me. I only have to do it once per year and it keeps them in check and does not seem to hurt the mother trees, although I’m sure it’s not great for them ha ha. I don’t do it too close to the mother trees though, I give them about a 10 yard buffer

I have the same issue with a honey locust. Suckers popping up all over. The roots clearly extend way beyond the drip line. Even under a 2 car driveway. My lawn mower takes care of them easily. Maybe you need a more powerful mower. Sometimes they pop up in gardens. I pull them the best I can and they usually give up after a while. Sometimes I get out the shovel and dig them up.

But honestly, if you just mow your lawn you will hardly notice them

Bill, I've often heard poplars referred to as weed trees and living in the land of the poplar, I fully agree! Yeah, they have their purpose, but sure ain't any bit the quality tree of a maple, oak or birch!! Other than the occasional extra nice poplar specimen, never much as bothered me putting a power saw to one or 100 !!

Oh, I agree, most Populus spp. are spreading or suckering trees. And if left to themselves, will turn everything around back into woods

I've seen instances where a stand of mixed forest trees, with some poplar scattered in among them, was clear cut and the root shoots from those scattered poplars, came up so fast & thick that it basically created a clear stand of poplar woods.

When I used to burn wood for heating, we liked poplar, it burned clean, was plentiful and not too heavy when dry. It replenished itself quickly where trees are concerned. I used to cut and pile in the winter months. I was always 3-4 years ahead with my cutting.

Who knows, maybe this wood was from same tree that was here thousands of years ago, and it just kept sending up shoots! ;-)