Those are pesky little buggers and a constant invader here in Sacramento. Although it’s been beastly hot for about a week, hot weather makes Roundup work faster. I still pull weeds near roses as they really don’t like Roundup. I’d try solarization. It does work here. A friend spreads four or five layers of newspaper on the ground, holds it down with rocks anc covers it with mulch. By the time the weed seeds are dead, the newpaper has decomposed and you are ready to plant. (At least, she was!)
Finally got out seriously yesterday (Independence Day) and declared my independence from the weeds. I unloaded two 1 gallon Round Up refills in my sprayer and went to town. I hit both the back and front yard gardens so don’t worry that unloaded all of this on the garden railroad…I used the “4 month” spray which was a few $$ more than the regular and saw results in about 3 hours. Not everything showed signs of dying so I’ll watch a day or so then go back in and hit again.
Ah, you nuked the buggers.
Today I went nuclear for the 2nd time in a little over 2 months. I’ve been using the 4 month Roundup with good results so far. A lot less to hit today than the first time. So I think I’ll just get on a schedule and hit things every few weeks or so. Should keep the weeds contained…hopefully.
I believe if you keep at it, you will eventually kill the really entrenched ones.
Then a monthly spraying of Roundup should be all you need.
Here’s what I use to help control spurge and oxalis in my lawn. It’s the only thing I’ve found that will touch spurge that is not a broad spectrum herbicide (e.g Roundup).
Plant leaves wither and die within a few days. May require a 2nd application to control new plants that sprout after the first application.