Any ideas and tips to control this weed - I'm not sure what it is. Will a pre-emergent like Dimension or Tenacity help with this for next year? I live in Northern Virginia - temps in mid 90s right now, so not sure if a) there is Post-E that kills this stuff or b) whether I should use one anyway, given how hot it is.
I think it looks like Asiatic Dayflower. You'll know for sure if it blooms. Asiatic dayflower produces the most vivid blue flower you've ever seen.
If that is what it is, it's easily controlled by hand weeding. It has a lot of top growth with an unbelievably small root zone. It's an annual and very frost tender. But the seeds are long lived and most likely carried by birds.