Unless you paint the stump with full strength brush killer. 100% they will sprout new growth. Ask me how I know, lol.

Use an old paint brush and as soon as you cut the top off, paint the stump. Make sure it is not going to rain anytime soon.

Digging them out is always the best way. If you can't manage that, cutting them off at ground level and painting the cut stems with an herbicide like glyphosate or triclopyr should do it. Just be very careful using the herbicide around any desired plants. Carefully paint - not spray - the full strength herbicide only on the cut stems.

May take more than one application.

Are you sure they are seedlings or are they sprouting from tree roots?

tj

They are not sucker but seedlings away from the mother tree. I have oak and ash tree. If I miss pulling out young seedlings, they grow fast and will emerge 2 to 3 feet in couple seasons.

I can use a long arm clipper to cut the stem to the ground, but digging them out or painting the stump with weed killer isnt easy as they are hard to access inside desirable shrub. Dont weed killers need contact with foliage to work.

No, the fresh cut stump pulls the poison to the roots.

I got rid of lots of European buckthorn that started up in my lilac hedge. Used a loping shear and glyphosate. I even cut down several large Siberian elm trees, some 12" in diameter, painted the stumps around the phloem layer only and haven't seen any of them come back and that was several years ago now.

Just don't spill any amount of glyphosate onto the roots of desirable shrubs. I lost a few lilacs that way.

"I am referring to 2 to 5 feet tall seedlings"

Pull them while they are small enough to come out easily.

Letting them get to this size is madness and now you know why.

Otherwise, crawling in the dirt to apply concentrate triclopyr to the freshly cut stem will do it.

I pull out small seedlings by hand only if I can spot them. There are always some I missed and when they peep out from the shrub border, they are already 2 to 5 ft tall.. Most seedlings dont make it underneath the shrub, but the few that make it through grow very fast with skinny stems in one to two seasons. These seedlings can only be pulled out by heavy digging.

I would not call a 2' tall tree a seedling. I have purchased trees that big to plant in the yard.

For Seedlings I have found that cutting them off will be all that is needed to kill them. Depending on where they are I have used every thing rotary mower, loppers, to pulling them out by hand.

2" = seedling. 2' = sapling.

A facetious answer to the question would be 'do it before they're that big.' At 2" you could hoe them off in seconds.

Ok, they are sapling, not seedling. There are hundred of seedlings on my lawn at certain time of the year which I mowed them down. But those that fall into the shrub and perenial borders will peep out as 2 to 5 ft tall sapling in one to two seasons. They are tall and skinny like vine, impossible to pull without digging.

Cut them with a lopper of an axe. It they return paint the stump with a poison.