[bityard]

Not who you replied to, but we do this with our kids. The only things are you need are a milkweed patch (there are many varieties besides the big ugly broad-leaf ones you see everywhere) and and a mesh enclosure off Amazon for a few bucks. The process is:

You go out, look for the tiny eggs on the milkweed, bring the milkweed leaves in, wait for them to hatch, and bring in fresh milkweed leaves for food once a day. We put them in a paper-towel-lined baking pan so that they have something soft to crawl on if they wander off to taste-test new leaf. They start out rather tiny and grow to into big fat caterpillars. Eventually they stop eating to go on walkabout and anchor themselves somewhere near the top of the enclosure. (Sometimes they are dumb and you have to relocate them with pins or tape.) Once they emerge as butterflies, set them free.

We do black swallowtails too. They like dill and parsely.

We never get tired of it. We have had 20-something butterflies at a time in a 2-sqft enclosure.

[WheatMillington]

Do you really need to go though all this trouble? We just plant a bunch of swan plants (milkweed) and watch the caterpillar and monarch populations go nuts. Add a bunch of flowers they like too (like zinnias) and that's about all I do.

[crucialfelix]

The survival rate is only about 6%. If you put them in the enclosure most of them survive.

We just stayed at a fireplace where they do it. It's very satisfing, no trouble

[zhynn]

Not sure if the wild milkweed out here in VT is the "big ugly broad-leaf one", but I think they are amazing plants. And I love the alien-looking pods with the almost fractal arrangement of fluff seeds inside. The flowers are interesting too if only because of their brevity, they only last a few days. I love watching the milkweed grow over the summer. Burdock too. Incredible plants.

[cmrdporcupine]

Yeah it (Asclepias syriaca) is a really interesting lovely plant. I let it grow in patches out in my back field (southern Ontario). Last few days there's been some monarchs flapping around there breeding. Kinda wish I'd let more grow, but if I don't mow back there the whole area gets overrun with sumacs.

There was a company out of Quebec that was trying to commercialize making clothing with the fibers from the seed pods. They're not quite long enough to spin, but they make an excellent substitute for down for stuffing.

I have to wonder if some good old fashioned selective breeding could produce a milkweed variety that produces fiber in the pods suitable for textile industry.

[bregma]

There was a selective breeding program during World War II to make rubber from the milkweed latex. I swear the annual crop from my back forty could have supplied the entire allied war effort but evidently the quality of the rubber was poor and alas the effort was abandoned.

The fiber on the silk from the mature pods is too short and lacks the scales that cotton has to make it useful for textiles. It is the bast fibers from the stems that make fairly good fiber but the moisture content is very high so unlike flax the fiber tends to just rot during retting.

[cmrdporcupine]

Yeah the QC company is using the silk for stuffing for mittens, as a kind of down replacement: https://lasclay.com/en/products/mittens

Which seems promising to me, at least.

Again it seems like a plant that with some smart old fashioned selective breeding could be made a lot more useful. But that kind of horticultural work has on the whole fallen out of fashion, it seems.