I recently took some cuttings from a number of green-flowered milkweed plants which were growing near the highway out by the wind farm in Muenster Texas. They're either A. asperula or A. viridis, I think. I see that this website: http://asclepias.homestead.com/flowers.html gives a few pointers on telling the difference. I trimmed the flowers off of the cuttings before setting them in vermiculite to root, but based on the narrow leaves, I think what I have are asperula. Are there any other obvious things to look out for, to tell the difference?

Also, I'm wondering how these milkweeds will behave in the garden (assuming some of the cuttings root successfully). I've only ever grown the tropical milkweed, A. curassavica, and I assume that the wild Antelope Horns won't be flowering steadily through the summer like the tropical milkweed does. After its blooms turn into the signature 'horns', does the whole plant just fade away like a daffodil until the next spring, or...?

Oh, and is it even possible to grow these guys from cuttings? I found info online suggesting that some kinds of milkweed can be grown from cuttings very easily, but no specific info on Antelope Horns. I guess I'll find out one way or another, but I'd like to know if anyone else here has experience starting native milkweeds from cuttings.