Been in my garden two years and is already a sizable clump.
There is a lot of variability in the blooms but I enjoy all the looks. I got around 6 weeks of blooms last year.
I've grown RATTLESNAKE RAKE for several years and it does well in my zone 5 garden. It increases well. It is an EM bloomer reaches it registered height of 30 inches. Bud count is 10 to 15. The pattern is consistent and blooms tend to look like Betja's image. Certainly displays the tet George Jets On pattern. Certainly an unusual plant in the garden.