How do you deadhead? do you just strip the old petals off or do you cut the stalk? mine bloom and then there is another taller stalk, kind of stacking- sometimes with a green round thing on it (what is this?) and i have problems keeping them in bloom all summer. the vegetation stays nice. i tried cutting the stalk last summer but didnt get another bloom when i did that. i love my cannas. they stay in the ground all winter and come up every spring (with lots of mulch-and on the south side next to the house). thanks in advance. joan