I agree that it's probably Dichondra. Fairly common as an alternate 'lawn' plant, in some locations.

Claire, I think it's too early yet for Gooseneck loosestrife to be blooming in the OP's zone 5 garden. My ND neighbor has it and his is barely up. whitegarden - the link below displays some photos of white Veronica spicata in bloom. Here is a link that might be useful: White Veronica spicata

No it has never had leaves. Not for my friend or me. - but you helped me identify something I find in my yard sometimes :), Thanks you for the response!

Here is what mirabilis (4 o clocks) look like with Mystic Beauty. Blooms are show and last until fall. Self sowing, but easy to recognize and pull out. I originally got this two years ago because it was supposed to be poisonous to Japanese beetles, but the it blooms after the JB peak. I notice that JBs have become less of a problem especially this year but I am not sure if that is more due to my vigilant picking them every morning for two years in a row. I also have a yellow mirabilis but it has not bloomed yet.