thanks! I was thinking the shoots were tree related. we have an old lilac that needs to be chopped down. do you think killing the lilac will kill the suckers?

like I said, we absolutely will NOT use roundup. it harms bees and therefore harms the food chain. so I'll try smothering with the old doors.

If applied properly (according to the label instructions), RoundUp/glyphosate has NO impact on bees. Or small animals or any other type of wildlife.

The suckers under the deck are not lilac. Possibly a willow? Or a plum?

Use a brush killer with triclopyr as the active ingredient. (It's more effective against woodies than is Roundup.)

Then use a disposable 2" plaint brush to paint it on the exposed growth to gradually starve the roots.Between paintings, store the brush in a closed rigid container you've tabled with the contents.

Depending upon how extensive the root system is, it may take 2 years or so but you won't need to dismantle anything.

I can't get direct access to most of these. my deck is only about 10" above the ground. also, it appears these are coming from my plum tree which I'm hoping to not harm. I suppose I'll try to smother these with heavy flat objects (old doors) shoved under the patio. that's just about the only thing I can think to do at this point, besides ripping up the deck.