Welcome to the Butterfly Forum!
In this area, when I start tropical milkweeds from seeds, they grow real fast and bloom the first year. They usually don't return after winter, but one of my plants DID return this spring! I love tropical milkweed, because the blooms are so attractive to all butterflies, as well as being a preferred host for monarchs.
The swamp milkweed will probably bloom this year, probably depending on how "happy" it is, but I haven't grown it enough to say for sure - maybe somebody else will know for sure.
Sherry

I have not grown swamp milkweed, but from the tropical seeds that have germinated in the past year, they all bloom as soon as they get over around 10" or so in height. You will find lots of help on this forum, welcome!
The butterflies thank you.
kelly

Thanks so much, Sherry and Kelly! I do feel welcomed here... so here's another question.. lol.. how tall and wide does the tropical milkweed get for the entire growing season? can't the tropical milkweed be brought inside for the winter if they're in pots? Do they have to be in full sun? part shade? do your host plants get all decimated during the caterpillar stage? if so, do you trim the plants after the cats turn to butterflies and does the plant bloom again? thanks for any answers.. love the butterflies and excited to breed monarchs!

I fertilize my tropical milkweed a little, so it gets to be about 5' - 6' tall. Once it gets over about 4 1/2' or 5' tall, I quit fertilizing it, because if it gets much taller than that, it'll bend over to the ground after a rain and need to be staked. It gets about 4' wide for me.
You don't have to prune the plants after the cats eat the leaves - and they'll eat ALL of them! - because Asclepias curassavica/tropical milkweed resprouts on its own. I usually do cut it back to about 4' tall, however, and fertilize it a little again to help get it going again quickly for more cats.
Tropical milkweed likes a lot of sun, but mine doesn't get a whole day's worth, because there are woods on one side of my garden. I'd say it gets about 3/4 of a day's sun. If you're in Seattle, where I assume it's much cooler than here in summer, I'd imagine yours would need as much sun as possible.
You can raise tropical milkweed in pots and bring those pots in during the winter, but I did that with several plants this past winter (4 or 5 plants) and only two survived. I don't know if the roots stayed too wet, or they need more heat than they got. I don't have a (heated) greenhouse.
Tropical milkweed works great for me, makes copious amounts of seeds, I even find volunteer seedlings on the ground near the plants. Most of us on the Butterfly Forum are in the hot/humid Southeast or very hot Texas, so I'd be interested to know how yours does in Seattle.
{{gwi:461722}}
Keep us posted!
Sherry

Thanks so much for all those infos, Sherry, they're very much appreciated! And yes, I'll keep you informed on how it will turn out. I hope I get to have monarchs too like you guys in the southeast do. Wish me luck!

Hi bulletz. I am in zone 7, and I grow Tropical, Swamp, and Common milkweeds here, as well as Butterfly Weeed. I find that the Monarchs that come through here seem to prefer the Tropical Milkweed, and that is what I use in my butterfly rearing tent. My very butterfly savvy friend tells me that she believes that the Monarchs prefer the more tender leaves of the Tropical Milkweeds. I wintersow the Tropical Milkweed and have great success with that. The plants grow large and bloom profusely each season. I do also have some Tropical Milkweed coming back from seed in my yard. Swamp milkweed just does not see much Monarch action here. Not sure why. Maybe it's because we offer the other options?

Thanks, bandjzmom! I do have a lot of tropical milkweeds sprouting, so I'm covered in that direction. I also wintersowed the tropical milkweed seeds! Isnt wintersowing great? I get lots of plants that way, with no problem with the damping off and hardening. Do you have a picture of your milkweed plants? And what is a butterfly rearing tent? You bring them in when they're in their egg stage and rear them up to butterfly stage? Can you explain that further, it sounds interesting. Do you do that to all the eggs you have? Does that mean that your milkweeds get to stay 'un-decimated' for the whole season? Lots of questions, but I just wanna make sure I'm doing the right thing. Please bear with a newbie, guys! Thanks so much...

Well bulletz, I actually let the Monarch moms lay their eggs on the milkweed which is growing out in the flower gardens. Then, I collect the little cats once they have hatched. I bring them into my butterfly tent which I keep on my porch, and put them onto potted Tropical milkweed plants. I keep the frass vacuumed out with a hand vacuum. I will send a private e-mail your way re:this. I have also raised Eastern Black Swallowtails (on fennel), Sleepy Oranges, and Cloudless Sulphurs (on senna) in different containers.

hello
bulletz - I have over wintered tropical milkweed in my basement greenhouse, and with a temp of 65 to 70 and some shop lights they over wintered fine, I didn't bring in the whole plant I just took cuttings and rooted them then tended them during the winter. I had to buy trop milkweed this year though becouse we are trying to sell the house and I have to dismantle the greenhouse :( but I just got them yesterday so I'm ready for the flutterbyes.
michelle