Saturday, November 20, 2010

Sullivant's Milkweed

Sullivant's Milkweed, Asclepias sullivantii, photographed last July at Killdeer Plains Wildlife Area in north-central Ohio. Killdeer Plains is legendary among birders for its raptors and other interesting birds, but the 9,000+ acre area also supports some of the best surviving prairie vegetation of the formerly vast Sandusky Plains prairie. This prairie heritage is one of the reasons the place is so good for birds.

Of the 13 species of Asclepias milkweed found in Ohio, Sullivant's Milkweed is my favorite. It really is showy, with luxuriant domes of rose-pink flowers that are considerably brighter than the somewhat similar and far more widespread Common Milkweed, A. syriaca. This plant speaks to our prairie past, too - it is essentially an obligate prairie plant, and is not found outside former prairie regions. Thus, it serves as a relict of our past; a botanical epitaph of the vast, incredibly diverse prairies that once blanketed some 5% of Ohio. This milkweed was originally discovered in prairies west of Columbus by William Starling Sullivant.

Sullivant's Milkweed tends to be shorter in stature than Common Milkweed, and has a promiment pinkish midrib on the leaves - a feature that stands out from afar. Killdeer Plains supports many sizeable colonies, but overall the plant's populations have plummeted in tandem with prairie destruction. It is listed as threatened or endangered in several states, and I wonder if it shouldn't be added to the Ohio list.
This Broad-winged Bush Katydid, Scudderia pistillata, was happily snacking away on Sullivant's Milkweed flowers, demonstrating its bulletproof constitution. Milkweeds are loaded with toxic cardiac glycosides, but apparently orthopterans such as this katydid are immune.

Of course, the most famous of milkweed snackers dotes on Sullivant's Milkweed, and our ancestral prairies must have been rich in Monarch butterfly production because of this milkweed. Here, a tiny gemlike egg is in the foreground, lower left, while the caterpillar lurks behind.

The black-yellow-white bandings of Monarch caterpillars warn off potential predators. The ornately marked bags of goo are poisonous, just as is their host plant.

Monarchs congregating en masse, staging for their spectacular journey to high elevation fir forests in Mexico where they will overwinter. Countless millions of these most recognized of butterflies must have once been reared on Sullivant's Milkweed in our former prairies. Not anymore; nearly all of the original prairie - Ohio and elsewhere - has been lost to the plow or other development. Good thing the Monarchs are adaptable and can use other milkweeds.


Janet Creamer said...

Great post on a beautiful flower, Jim!

Jim McCormac said...

Gracias, Senorita!

Corner Gardener Sue said...

That's a nice looking milkweed. I listed our yard as a monarch waystation. I have planted several kinds of milkweed. Not all survived. I'm hoping a couple of them just went dormant last summer, and come back up in the spring.

Kris Wilcox said...

I have a plant that looks like Sullivants Milweed growing in my sandy Florida pasture. It has the distinct pink ribbing in the leaves and the pink flowers. Could this plant be growing in North Central Florida? could I send you a picture?