I tried a package of the pink (there is also a white) variety from Park seed. They did not bloom the first year, perhaps one of the reasons why was that I under watered them early in the spring and some of them went dormant for 2 months during the summer before reviving. As they dry out the leaves turn yellow and then bronze and drop off. So it is important to keep them fairly damp when you are just starting them. They bloomed a little the second year, the blooms have a faint vanilla scent, different from common milkweed. They are not as impressive as the orange butterflyweed.
Monarch butterflies lay their eggs on these plants so by growing some you could end up increasing the butterfly population. Butterflies also favor the nectar found in the flowers. Take care not to place the plants next to 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 the various milkweed plants and 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 butterfly weed 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, in 2000 there were hardly any.
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. Pinch off the seed pods to encourage more blooming.
Wild seeds require cold treatment and light to germinate, well-bred seeds only seem to need light, see How to Start Seeds for details.