looks Phlox paniculata the common garden pholx

Thanks for your reply. It may be a phlox, There are similarities but it is different than what are in any of the gardens around here,

These are much shorter, have much fewer flowers and also as I wrote before it only seems to grow in the cracks in the pavement of our alley and not in open soil. There is one garden next to the alley and they don't grow there. Interestingly, I haven't seen it growing even in the next alley across the street or on the next block. It is puzzling.

Maybe it is a native/wild variety.

Thank you again!

I still think it is P. paniculata. The native plant has been cultivated to produce many different varieties but when it becomes naturalized the natural traits begin to return after a few generations.

OK Thanks a lot. I'll search for native phlox and see what I come up with.

Again, Thanks for your help.

Thank you. I will look into this one too. It does look more like it.

Growing in cracks in the pavement, the plant is probably smaller than normal size because nutrients/moisture are inadequate in the soil under the pavement. There may also be undesirable chemicals in the soil (if asphalt), or a pH (if concrete) which is not ideal for the plant, or oil from passing cars -- any of those could be a stunting factor.

Maybe watch it carefully for seedpods, and scatter seeds in your garden or start some in pots?

Not Phlox paniculata. The leaves are totally different from Phlox'.
It is Silene armeria..