Sullivant's Milkweed, Asclepias sullivantii
 
Sullivant's, also called prairie milkweed, is very similar to common milkweed but not as aggressive. This makes it a perfect choice for a garden plant. The large, fragrant pink umbels flower from June to August. It will hybridize with common milkweed.
It is a species in decline in Ontario due to habitat destruction.
 
Ecology:
Sullivant's milkweed is the host plant for the monarch butterfly.
It is a very attractive nectar plant for many bees and butterflies.
 
Growing Conditions:
In the wild,  Sullivant's milkweed is part of the tallgrass prairie ecosystem. Prairie milkweed requires full sun, thrives in regular to moist conditions, but can tolerate medium-dry conditions. Its long taproot makes it drought-tolerant once it's established.