Will the sun rise tomorrow? Truely we don't know.

Probably, just keep an eye out near where it was planted. It IS a perennial (grows back from roots every year) if that's what you are wondering.

What I meant was, does it only come back from seed, since mine didn't make seed.

No, as skip said, it's a perennial.

However, from my own experience, it either loves your site or hates it, so who knows if it will return or not.

It's a very easy plant to grow. I would suggest that, at the end of the summer, you pick up some seeds and sow them around to have more next year.

From what I hear (but can't validate myself), it spreads relatively rapidly underground (if it survives), btw mine popped up a couple days ago.

It has spread extensively underground for me. That's why there is so much extra to give away. Mine hasn't emerged yet, but the swamp milkweed is already showing.

If you need plants I could bring you some, and we can meet at the native plant sale on Laraway rd. May 18th! There is a good chance your plants will return and which case forget everything I said lol.

Oh my, I just went up to move the milkweed. EEEEKKK, I've created a monster. Roots 5 feet long! Do I really want this in my yard? Is there any way to control it?

You can dig it out of the spots where you don't want it. It started spreading in my yard for a few years during which time I never saw any Monarch caterpillars. Last year I was swamped with Monarch Caterpillars and they ate all my milkweeds down to sticks. I had to drive out to Woolhuos in Manteno and buy 8 more milkweeds. I have another garden where they have gotten too numerous. I'm going to thin them out over there, but still keep some. There are other native milkweeds that don't spread like that! Syriacas are used by more eastern Monarchs than any other milkweed. They've evolved great powers of regeneration to combat constant predation. I think they are worth growing even though they are a bit agressive.

Thanks Jay; I should have said "runners" instead of "roots". I also have a swamp milkweed.

You must have done a good job growing them. I have a colony of syriaca in a full sun situation, and it spreads like crazy, but some of my vollenteers are in part shade or deeper, and those milkweed stay behaved. One (plant) that has gotten part sun for several years now still has only 2 main stalks with a smaller stalk that continuously grows back after being eaten. Remarkable regeneration. The other plus you get from having them in part sun is the leaves stay fresher and greener much longer than the common milkweeds that have been in full sun all summer. The Monarch caterpillars prefer to eat the tender new growth of the milkweeds. The fuzzy tussock caterpillars that feed on common milkweeds prefer the older, tougher leaves. After several years of decline the eastern Monarch butterfly population rose last year. A lot of us worked to make that happen.

These 2 Asclepias syriacas have been here several years, but still only have 2 stalks because they are in part shade. One drawback, the part shade setting prohibits them from ever flowering and setting seeds. There are some milkweeds that prefer a little shade like variegata and exaltata. I just can't wait for the native plant sale!

Update: I now have 6 plants sprouting where I thought I had dug it out, LOL!