Over the last few years, an aggressive, leafy weed has gradually taken over the grass of my back yard in Northern California. It spreads its roots horizontally and occasionally sprouts up purple flowers on a short stalk. It smothers and outcompetes the grass in areas where it grows.
And here's the plants growing back a few weeks after I thought I'd ripped them out by the roots.
I've never seen this plant anywhere else other than our back yard. No idea how it got there, but it's slowly but surely eating every square foot of our yard. By next summer there probably won't be any grass left. ;-(
I've tried to rip it out by the roots and it just grows back times 100. The roots seem to grow horizontally underground and when the top parts are removed (along with at least some some of its roots) then new sprouts proliferate from the remaining roots I didn't find. It's not like dandelions which sometimes come back in the same spot. It's more like a hydra (the mythical kind, not the plant) where you chop off part and it comes back even stronger.
Our gardener tried weed-n-feed which didn't kill it. Now he's suggesting that I'll need to kill the whole yard with herbicide, wait a few months to make sure the weeds are really dead, and finally re-sod it. Are there any alternatives?