I would not do it. You likely won't see monarchs until early June. If you want monarchs laying lots of eggs on your plants, you don't want old plants. I'd suggest having your milkweeds seeds sprouting around the 1st or 2nd week of May. The trick is to have young plants that are attractive to egg laying monarchs plus have enough leaves to feed the caterpillars. In my experience, monarchs' favorite milkweeds to lay eggs on are around 2" tall. So when I say they like young plants, I mean YOUNG. Once you get your milkweed established, make sure you check the tiny plants that are coming up later in the year. They will come up from the spreading rhizomes.

I think it is Asclepias fruticosa - aka White Swan Milkweed or Cottonbush. It 'might' be Gomphocarpus physocarpus aka Asclepias physocarpa 'Oscar' but based on the amount of blooms and stalks in your photo, I tend to think it's Asclepias fruticosa. Both are easy to grow from seed and both are frost tender. I like to grow it for the small tender leaves, which are excellent sources of food for the Monarch babies. Mary

I understand now, wantonamara -- thanks. I do recall my milkweeds forming pods, bursting open and blowing away pre-winter. The seeds pictured definitely 'died on the vine'. docmom_gw replied to my separate inquiry and says it could be goldenrod. The flower shape (feather-like) definitely looks right, and I can see how the leaves might resemble milkweed: Appears to be rather invasive for a garden that needs to support other plants), despite it being great for butterflies, bees, etc.

I wouldn't be too dissapointed. Tansy is a very agressive plant that is almost impossible to control in a garden. You have one of the prettier leaved Tagetes. It looks close to Tagetes lucida, Mexican Tarragon. Yes, marigolds can smell like licorice too. I fell in love with Tansy when I first saw it. Started growing a plant that was soon 3 plants, then 5 plants. Realizing it would take over my garden, I got rid of it.