Unknown plant or very prolific weed
Can you provide any more information? When did you begin to see this weed? Was it in the yard last year? Is it hairy underneath and does it cause any dermal irritation? It looks something like clearweed, Pilea pumila, except the darker leaf color.
I closed on the house on June 16th. When we started the purchase 45 days earlier, the plant was 1/4 the size it is now. The owner says she vaguely remembers having a potted plant that she dumped there after thinking it died and it popped back up the next year.
We have been clearing it slowly, but you can see that it is popping up all over near the large bush that it is now. So far, it hasn't given us any kind of reaction or make us itch. I looked at the leaves and it did not seem hairy underneath either.
It is a dark green with very strong streaks of purple. Weird right?
It might be Perilla frutescens, also called perilla mint. This weed emits a minty odor when the mature leaves and stems are crushed.