If you can mulch heavily over them that might help. I use cardboard, wet it, and then put bark over it. Great for the soil and worms love it. Should stop the buttercups, except maybe right next to your other plants. Leave about a 6" square opening around existing plants.

Lee

I have these is a patch of lawn and the patch is getting larger and denser - about 7x15 feet at this point. It is next to a perennial border which is sep. from lawn by a trench but buttercups of course still creep over to border where I hand weed them out. I am sort of a live-and-let-live lawn person and tolerate about anything that is green and comes up, but this buttercup patch has gotten enough larger and denser this summer that I think I'd better do something about it. I HATE to spray. Never do. But is this the only option? And what should I use? And will that work?

thanks

Deborah

There are many species of Ranculcus called buttercups. The above idea to smother them with cardboard is a good one. You could also get out your shovel and dig them up. Whether you have the annual or perennial kind, there are probably many seeds on the ground that will be ready to sprout when the conditions allow it. So smothering might be best in that case. Cover the cardboard with mulch, and maybe put a single shrub (just 1 hole in the cardboard where you can easily control sprouts by pulling) so it doesn't look like an "empty space." You can maintain this space by simply pulling weeds when they sprout in the mulch (from seeds dropped by birds and blown by wind) and adding more mulch once every year or two, or let it decompose so the grass can creep back in.

Do you have the "Ranunculus" species or the "Oxalis" species? Is there a root system, "Ranunculus" or bulbs, "Oxalis". Plants that are kin to Yellow Wood Sorrel known as "Buttercup", "Oxalis", are considered "weeds" and cna be difficult to eliminate from the landscape and some are hardy enough that smothering, or depriving them of access to sunlight, does not deter them them.
Often, when a "weed" is spread by seed and new seeds germinate people think the "weed" they pulled last week has grown back when it is a newly germinated seedling.