When should I mow down blk eyed susans?

When they look tatty enough that you can't stand them anymore, or after the foilage dies back in fall, whichever occurs first. BTW, I have fround with most of my 'daisy'-types . . . shastas, rudbeckias, etc., that, if I mow them down right after the first flush of bloom fades, I'll typically get a second flush in very late summer or early fall.

Chris Owens

I just realized Black Eyed Susans are the state flower for Maryland in the U.S. I assume that means this flower grows well in Maryland (even without much human attention). What did Maryland residents do for their climate?

Mine seem happy with the 'throw seed heads in the general direction of the ground and leave alone' method.

I do sometimes deadhead them, but my R. hirta and R. fulgida don't seem to care one way or the other. Maybe I haven't deadheaded them promptly enough.