Question
My lily of the valley is too thick and trying to grow into the lawn. How do I thin it? I've tried pulling out SOME, but they break off. Currently I am digging out big clumps here and there, trying to get lots of the root systems. I'm not sure how those lilies will look next summer. Will the empty clumps fill in?

Answer
Hi Marg Huey,
I have lily-of-the-valley in my front hard behind some bricks.  It always starts popping up in between the sidewalk cracks and bricks.  You can spot treat it with Roundup but be careful not to get the Roundup on anything else.  I dig clumps out too and they always fill back in rather rapidly.  It's a constant battle controlling them but I love their heady scent when they bloom in the spring and the delicate little bell-like flowers.  Just keep digging or using Roundup.  That's about all you can do.  I hope this helps.
Tom