Thank you Irving Ragweed for passing along your experience with 20% Horticultural vinegar. I had read that great care must be taken with using it as being a strong acid can cause damage to skin and eyes. I hadn't thought about the fumes.

Yesterday I sprayed 9% vinegar from HEB. It seems to be a little more effective. The prostrate spurge and unwanted white wine cups were dried up within a hour of the treatment. But it had little effect on the Cedar Elm seedlings as you can see from this photo:

Here you can see it killed the tops of the white wine cups, which are beautiful plants, but I didn't want a whole 'lawn' of them. Not sure whether the carrot like roots are killed so that they will not come back, they do seem much easier to pull up now so perhaps so.

I am pleased that this area is pretty well cleared up. The better mannered self seeded black foot daisies and four nerve daisies were left in place:

But there are many square feet of gravel in the front yard and back where the vinegar resistant Cedar Elm seedlings are thick thick thick. I've laid a plastic bag over them just to see how long it will take to kill them. I'm not very hopeful it will be a solution ...

I've pulled them by the hundreds. There are millions/billions more. Bob said he will try pulling the hoe over and through the rocks to dislodge the seedlings, but I don't have my hopes up that it will be a viable solution and it would certainly be a lot of work.

Suggestions?

You have millions/billions of cedar elm seedlings? Some gardeners have all the luck. The only unplanned trees that volunteer for me are box elder and hackberry.

If you're not in a hurry, you could let the seedlings thin themselves out. There's no way that many seedlings can survive their first growing season. If you let natural selection run its course, by the end of the growing season you'll be left with only a handful that should be easier to deal with. Obviously, in the meantime the weeds are detracting from the intended aesthetics. If you want your garden paths to look like garden paths instead of a scene from 50 Years After Humans Have Become Extinct and hand-picking is impractical…

One alternative is to dislodge every weed with a heavy-tined rake. Based on your photos, this would require removing the pavers and gravel so the rake can penetrate the soil. Once the hardscape is out of the way, raking up swaths of weeds would be a cinch. Weigh the labor involved in removing and replacing the hardscape vs. hand-picking, then choose your poison (glyphosate excluded). Regardless of the approach you prefer, everyone knows that disturbing the soil is an open invitation to countless new weeds, which brings us to…

Long-term solution: Apply corn gluten meal as a pre-emergent to areas where you do not want any seeds to survive.

"There's no way that many seedlings can survive their first growing season. If you let natural selection run its course, by the end of the growing season you'll be left with only a handful that should be easier to deal with."

True wisdom spoken from the mind of a seasoned gardener! No one has dictated that the gravel must be pristine at all times.

My next question is: how well does corn gluten meal work as a pre-emergent on gravel? Has anyone on here used it with success?

I've used corn gluten meal only on bare soil, so take this with a grain of salt: If seeds can find their way through the gravel to make contact with the soil, wouldn't the CGM follow the same path? One would like to think the CGM would reach the soil as soon as you water it in.

I use the 20% vinegar almost exclusively in our community garden. It’s very hard to hand pick the weeds in a brick pathway So that’s my only choice. I’ve had great success with it.

Lorelei, thanks for passing along your experience with the 20% vinegar. SAWS (San Antonio Water System) recommended it in a recent newsletter.. Do you find it needs sun to work well? Also, where do you buy it?

Noticed in the last couple of days that a lot of the little Cedar elm seedlings turned brown after spraying with the 9%.. It just took them longer.

So far those under the black plastic bag have not shown any signs of dying.

I buy the 20% at our local Do it Best hardware store. I solarized a large area in the community garden with the black plastic . Everything died but 3 months later it all came back.☹️

Thanks Lorelei. I'll call around.

Here is the SAWS 'Garden Styles' newsletter about using 20% vinegar. I found out the hard way to be sure to rinse the sprayer very well after using.

Hi ragna, there is an organic product called EcoSmart weed and grass killer that is available in a sprayer. You are only supposed to use it where you never want anything to grow. Pavers,flagstone etc and it has to be hot for it to work, I know where to get it here in DFW area but don’t know of your area,

June, thank you so much. I'm checking it out. Nice to know other things are available. Looks like it's made with things like clove oil so should smell good.

I just picked up a gallon of 20% vinegar at my local hardware store for $17.00. I'll see how that works first. Stay tuned ...