Unfortunately, the best way to collect ripe seeds from these plants is to watch them every few days and collect the seeds as soon as the seed pod turns dry and starts to split. Even plants within the same bed will have ripe seeds at different times, just like they bloom at different times. If the plants are not near where you live, you could ask some one who lives closer to keep an eye on them for you. Best of luck.

Martha

Thanks for your input Martha! The plants are on the edge of woodland on my property...the problem is that I will be out of state until mid August. There are 3 clumps that I can see. about 8 plants in all and they are all flowering now so I thought since they were flowering at the same time, they might also have ripe seed at a similar time? Do you know if this species is susceptible to milkweed bugs?

I found a link that would give me approximate seed setting times. The times are for GA but it gives me a rough idea of how long it takes from blooming to seed collection.

In case anyone else is looking for same info here's a link!

Here is a link that might be useful: Asclepias info

If they've been blooming for a while, they have probably been pollinated already. You could purchase some tulle wedding favor bags and tie them over a few of the blossoms. That will allow the seed to ripen on the plant, but protect them from being released or eaten by bugs. You can also use cheap knee high women's nylon stockings. Hopefully, you'll return from your trip with seeds waiting for you in little bags. And I'd plant those seeds as soon as you have them. The fresher the seed, the better the germination in my experience. Try wintersowing, or actually late summer/autumn sowing. Good luck.
Martha

I've tried winter storage in my unheated garage. I'll put seeds in Ziploc baggies c name on outside and store all in a thick glass vase from Fall till Spring. Then I'll spring sow in liners inside to give them a little more of an edge. Then I'll repot into 4" and place out of reach of rabbits and other pests. When they've grown into these, I'll plant outside. So far, I've had best results c A. incarnata, which seems to be the most rabbit/gopher resistant.

Agkistrodon, did you collect the fourleaf milkweed seeds?