Butterflyweed is a prairie plant with bright orange flowers and a long bloom time making it a nice plant to have around the garden. Flowers come in waves from June to early September on older plants. The way it grows it ends up looking like a bush. So far I've had plants go to three feet four inches, taller than advertised in the Park Seed catalog. It will bloom late the first year if started early and given enough sun. Some nurseries offer it in yellow. Some catalogs call it butterfly plant or butterfly flower because they don't want to say "weed". Butterflyweed is not the same thing as butterfly bush (Buddleia).
Monarch butterflies lay their eggs on these plants so by growing some you end up increasing the butterfly population. Butterflies also favor the nectar found in the flowers. Take care not to plant butterflyweed plants near other plants that you use pesticides on. Here are a couple of sites that describe how to raise monarchs:
The oleander aphid (see photo from TAMU) likes swamp milkweed and butterfly weed. I've also found them on Heliopsis helianthoides. These bugs start out as yellow-orange eggs mostly on the stems in clusters, they then develop legs that poke through the eggs, eventually the egg is absorbed into the bug and you're left with a small black fly. They do not seem to hurt butterflyweed however I think maybe a large concentration of them will hurt swamp milkweed and cause the leaves to wilt. You can squish large concentrations of the bugs with your fingers or hit them with a strong stream of water or both. How many I get on my plants varies, in 1999 I had a lot, now in 2000 I only see some clusters on a few plants.
The plant forms banana-like seed pods that eventually burst open and because they have a cottony dandelion-seed-like parachute they will blow all over the place. I pick off seed pods early in the season to promote more blooming but I let the last batch of flowers form their seed pods since Chicago is short on butterfly weed :-) . If you want to preserve all your seeds you can tie a string around the seed pod or something like a piece of a nylon stocking will do.
Don't overwater as butterflyweed likes it dry. In hot locations it will start blooming in June but in cool spots you might not see it coming up until some time in June.
Butterflyweed grows a long root so its only easy to move a plant when its small, as it gets larger there is a good chance the plant will not survive a move. But if you let the seeds blow all over the place like I do you can always find a little one coming up somewhere.
Wild seeds require cold treatment to germinate, see How to Start Seeds for details. Well-bred seeds don't seem to need cold-treatment.