Thank you!
The tropical seed I harvested off of plants I bought at Lowe’s about 3 years ago(Lowe’s hasn’t had them since). I overwintered them in the house as a house plant. I collected the seed pods after they dried right as they were popping. You can get them on eBay usually.
The swamp milkweed which is hardy (zone 5 at least), I bought several plants last year from The local true value this last spring and again harvested the seed. You can also find those fairly readily on eBay.
The showy milkweed or common milkweed, I harvested pods from plants along side the road. For such a tough plant, it took me a bit to get some established. Wait until the pods are dry and start to pop before harvesting any. Look for cotton fluff on the plants to know when it’s time. This years bloom is about 50% done, and green pods will start to form. They grow long taproots and I find growing them from seed was the most success. Remember these plants are poisionous to livestock. They won’t eat them out in the pasture, but if cut with hay, the animals will ingest them and can kill a cow.
Best nectaring plants I suppose is a butterfly bush (Buddeliea), coneflower (echinacea), phlox, bee balm, lantana, zinnias are good.