What's this little guy called? I expanded my annual beds and built a hugel a few weeks back, and now this plant is popping up along the edges. I don't remember seeing it in years past. I'm in CT, USA, zone 7a.
Kris, it looks a lot like Shepherd's purse; that being said, sometimes watercress can sometimes resemble Shepherd's purse. I'm sure its in the brassica family, though. If you haven't planted cress in the past, with the seeds somhow running amok, it is likely shepherd's purse.
I have been encouraging dutch clover, dandelion, purslane and creeping charlie in the lawn. I think I'll just add this to the list! We have a 2 year old so a little bit of grass is nice for her to run around in, but If we have to have a lawn, I like letting it at least be a polyculture of sorts. I wonder if our mild winter allowed this stuff to proliferate? Maybe there was a little of it before? A closer look revealed tons of it mixed into one area of the lawn as well as around the new beds!
It seems unlikely that it would cross pollinate with Kale or cabbage, since it's a different genus. We have a LOT of it here that goes to seed before we can get to it, and have never noticed any cross-pollination. It also seeds quite a bit earlier than our brassicas.
Kris: I've never noticed a lot of aphids on it here.
R. Ranson, I just noticed today that in just about a month and a half, these little guys have entirely gone to seed and nearly disappeared beneath the other, more vigorous growing things. They certainly did go to seed long before my kale, bok choy, and mustard, which are still just about 6 inches tall, and nowhere close to producing seeds. Kevin's right