Yes, it IS hard to get rid of and very prone to rust. I refuse to carry it any longer at the nursery. One method you can use to help improve the appearance is to cut it back hard (or mow it down) when the rust appears and clean out the debris. As with a number of fungal problems, the new growth will come in clean. The heavy pruning also seems to stimulate thicker, denser growth, so the planting looks full and lush.

Thanks, I'll do that. It can't look worse than it does now. I was also wondering about mowing it and burying it -- I wonder if I can smother it?

Gardengal, it's just getting worse. I don't want to mow it down now because it would be a make work project that I can't deal with. DH wants to get rid of it. Do you think that if I mow it down, spray it with round-up and then bury the whole bed with 6inches of mulch or topsoil it would disappear? Or any other suggestions?

mowing it down and spraying it with round up does not help at all we did this last year and now it is full bloom again, i just want it gone, the only solution i can come up with is to dig it up roots and all.

What causes the rust? How often should this plant be watered? I have a very large steep slope planted and mowing it down every other year keeps it lush and blooming in the spring/summer. Now ugly rust moving rapidly through it. Wondering if it is getting too much water.