We'll now take a brief break from the creepy crawlies... (Sorry, lots more neat spider stuff to come!)
"If it blooms, it's not a weed." Unless it's where you don't want it.
Then it's toast. I am ruthless when it comes to wood sorrel (Oxalis) in the deck containers, native though it may be. I find it a lovely little wildflower, but it seeds itself everywhere. Prolifically.
At least it makes a nice subject for photo-fiddling.