old_eagle(7b - North Texas), it is so nice of you to want to grow milkweed for the monarchs. I don't have seed of this variety but hope someone has gotten in touch with you if they have seed to share. Even if you've received seed of this variety, the resulting plants will not put up enough growth to feed even one Monarch cat this season. Perhaps you might consider also growing

Asclepias
curassavica, aka Tropical or Mexican Milkweed, which will put on enough growth to feed some Monarch cats, until your perennial milkweed becomes more mature. An added bonus is the tropical mw will also bloom all summer, providing an excellent source of nectar for all the little flying garden visitors, including Hummingbirds.

You might check at Monarch Watch to see if they are offering free milkweed seed this season or check the link below for an offer of free milkweed seed for a Stamped Self Addressed Envelope, which I discovered when I googled 'free milkweed seed'.

Best of luck with your butterfly garden and thanks again for planting Milkweed for the Monarchs. ... Mary

Free Milkweed Seed offer

I have some antelope horns plants that are too young to have bloomed, so I only have a few seeds that I bought in case those didn't work. Some have come back already and some of them are looking vigorous, so I'm willing to share the few seeds I have if you will send me your address. I can't promise you will have success with just a few seeds, but it is all I can offer until mine bloom and I can gather my own seeds. If you like, I can send some other milkweed seeds gathered from my yard so you might get some additional plants.