Aphids love this plant. Though it may be unsightly at times, they do not impair blooming or growth. If you can't stand to look at them, you may use a strong blast of water or just remove them by squishing them with your fingers. Most insecticides are a no go on this plant because it is a host plant for monarch butterflies.

Please prune stalks down during fall and winter (late November should be good) so that the monarchs don't skip their migration. If they overwinter here, they can potentially spread a disease called OE that can result in the butterflies' death. The spores from infected monarchs can build up on these plants which is also why we trim and remove the stalks. It will not harm us, just the butterflies. 

Tropical Milkweed is not native to our area and has become quite invasive. For native options try Butterfly Weed (Asclepias tuberosa) and Swamp Milkweed (Asclepias incarnata). The natives are a bit more difficult to find, but I will do my part to make them more available. 

Please note, the sap from this plant can irritate the skin of some gardeners.