Ive grown many varieties an none need stratification.

Thank you so much Cathy, I didn't know that. I guess that I was lucky then to have Butterfly Weed, Swamp and Common MW germinate when I planted them in milk jugs last January. No need to do that again that early.

If you look at the milkweed seeds at Prairie Moon Nursery they have a chart that tells you if they need stratification. Most of the native milkweeds do need at least 60 days of cold. The A. curassavica and the other tropical milkweeds don't need cold treatment. The southwestern milkweeds? Some may need cold treatment and others might not. I just sowed a bunch of milkweed seeds tonight. I soaked them in warm water for 24 hours. When I was sowing the Asclepias arenaria seeds it looked like 1 or 2 were already germinating. It's more of a warm area milkweed so I'm not sure it really needed cold treatment. I ordered more arenaria seeds just in case. The ones you winter sowed last year did need cold treatment. I'm going to sow tropical milkweeds outside in February at the same time I start Zinnias and other annuals. It's pretty easy to just google germination or go to Prairie Moon before sowing each species so you know exactly what to do.

Thanks Sara. I did stratisfy butterfly weed last year and it did very good. I didn't know at the time the tropical didn't have to be stratified, I put them out with the others and lost them. This year I should do better and thanks Jay for the Prairie Moon information. They have a very good code guide on how soon seeds should be planted and helped me tremendously.

I think you also have to consider your own environment. Example: In my area of NC we have wet winters, mostly rain but sometimes ice and snow, and WS Asclepias in Dec. means seeds have a chance of rotting. I usually have better luck starting WS for them at the end of Feb. or into March, allowing for some cold exposure.