Poa

I had Lesco dimension put down in mid march. Did the pre-emergent just not work or does it take years of using pre-emergent to get rid of the thousands of poa seeds?

P. annua sprouts the fall before, so if the barrier wasn't up then, it had no problems. Even a good pre-emergent barrier is only about 90-95% effective, and in practice that's frequently lower. So although it would have taken care of 19 out of 20 sprouts (maximum), one out of twenty will still make it through.

Thanks for the advice.

I'm curious for the future, how are you able to tell the difference between poa and KBG sprouts?! Is it the color of the sprouting seed heads?!

It's more the color of the blade, which has a noticeable chartreuse tone to them as opposed to the KBG, which has more of a pure green note without the yellow in it.