Last fall I was able to purchase some swamp rose milkweed, Asclepias incarnata, from Craig Huegel who manages Hawthorn Hill Native Wildflower and Rare Plant Nursery in Seminole, Florida. Craig also writes a blog about native florida wildflowers that offers a wealth of information about native plants. The blog is searchable so you can look up a specific plant or just browse through it: http://hawthornhillwildflowers.blogspot.com.
The following is his description of Swamp Milkweed posted February 7, 2010.
"Swamp rose milkweed, Asclepias incarnata, is one of the most beautiful members of this genus and well worth making a place for in the home landscape. Native throughout peninsular Florida, it occurs in moist to wet soil habitats in sunny locations. In the home landscape, it needs similar conditions to thrive, but it can tolerate occasional short-lived drought once established. Swamp rose milkweed emerges in the early spring and eventually reaches a mature height of about 3-4 feet. The stems are stout and multi-branched while the leaves are lance-shaped, up to 6 inches long, and abundant along the stems. Blooming occurs in summer. Large rounded heads (umbels) of rose-pink, slightly fragrant flowers adorn the ends of each stem and are quite showy.
Use this species in small clusters of 3-5 each for the best effect and plant it in locations that stay wet in the summer months; the edges of ponds and other water features. Swamp rose milkweed is a favorite larval food plant of the milkweed butterflies - monarchs, queens, and soldiers - and it is one of the best milkweeds for nectaring butterflies of all kinds. If you decide to use it, however, keep it wet to moist during the heat of summer or you are likely to lose it."
Our plants are growing well and we are waiting to see them bloom.
References:
http://hawthornhillwildflowers.blogspot.com/2010/02/swamp-rose-milkweed-asclepias-incarnata.html
http://www.florida.plantatlas.usf.edu/Plant.aspx?id=3626
Photo by Craig Huegel