I bought an Eastern Steeplebush Spirea (Spiraea tomentosa) from a native plant nursery here in southeast Pennsylvania several years ago and planted it in a big tub pot. Last year I took some softwood cuttings in July and dipped the tips in rooting hormone and put them in a big pot with potting mix and put a plastic bag over it, and most rooted. I put them in little pots after they rooted. This year I put them in bigger pots. This year I am also trying layering by pulling down 3 different branch ends into pots and we will see how they do at rooting.