Milkweed is a common name that could refer to any plant that oozes white sap. It could also refer to the over 200 species of the genus Asclepias worldwide or the 12 native species in the USA. So which milkweed do you have? Which milkweed are you looking for?
In 2018, the Xerces Society published an article, “Tropical Milkweed—a No-Grow”. Read through it and you will learn that the title is somewhat misleading. Tropical milkweed, Asclepias curassavica, is only a no-grow in temperate regions. A. currasavica does not overwinter, so the Ophryocystis elektroscirrha parasite (OE) dies off with the plant and is not a problem. Note that all species of milkweed, not just tropical, can carry some level of the parasite. If you are Zone 7 or colder, growing A. currasavica is as safe as any native milkweed. It might even be a better option.
It is easier for insects to locate a plant, if there is plenty of it, a bigger dot on the landscape, not an imperceptible speck. It can take several years for tiny plants of native species to mature into good-sized clumps. Why not fill in the space with flashy, fast-growing annuals, A. curassavica or Gomphocarpus physocarpus (Balloon plant/Hairy Balls)? Both are excellent host and nectar plants that are well-behaved and do not spread aggressively. Physocarpus can grow to over 6’ tall, making them easy for flying insects to find.
How much milkweed do you want? Do you want it popping up all throughout your flower beds and taking over? Spreading into the neighbor’s yard? In the Mid-Atlantic USA, native milkweeds that do not spread via underground rhizomes are A. incarnata (Swamp Milkweed) and A. tuberosa (Butterfly Weed). A. purpurascens (Purple Milkweed) does spread, but not aggressively. Sidewalks do not stop Showy and Common milkweeds from spreading. Pulling them out is ineffective, as any scrap left in the soil will sprout.
Many argue that native plants are best. Although they do have their merits, they are not readily available in garden centers. A garden with more plants of all kinds will do a better job of feeding more wildlife than a garden with a few native plants.