One of the keys to having monarchs—for their survival now and in the future—is having lots of milkweed. Because of modern changes, such as suburbanization and Roundup-Ready crops, there's a lot less milkweed than there was in the past. This is a disaster for monarchs since monarch caterpillars can eat nothing but milkweed.
No milkweed, no monarchs!
We want lots of monarchs, so we plant lots of milkweed for them to lay their eggs on. We've tried to maximize our milkweeds in a number of ways—especially since it's sometimes difficult to find them for sale or at least to find them for sale at an affordable enough price to buy more than just a few.
Purchasing milkweeds: All milkweeds are of the genus Asclepias. When we look for milkweed seeds or plants to purchase, we always look for this name. Sometimes nurseries are afraid to call them milkweeds since people shy away from anything with “weed” in its name, and because milkweeds have an undeservedly bad reputation.
Some nurseries name them something innocuous like “pink butterfly plant,” but that doesn't help people who are looking for milkweeds! Knowing the botanic name is very useful and helps us find the real milkweeds (if the grower actually uses these more correct names).
An aside: We wish nurseries would offer six-packs of small milkweed plants rather than large, pricey single plants. They grow quickly enough that these large plants aren't necessary, and having one plant isn't going to really help much.
How will a monarch find one isolated plant? Monarchs usually lay just one egg on a leaf; they lay eggs on lots of leaves of more than one plant. And besides, how could one or two plants be enough food for the caterpillars that develop from the eggs of even just one monarch? These caterpillars are eating machines!
Gathering Milkweed Seeds
To easily collect the milkweed seeds—i.e. getting the seeds without the fluff—we collect the pod when the pod has split, and it has just begun to open rather than waiting for the seeds' little “parachutes“ to start floating all over.
Wait until you see the pod starts to show the split, though. If you open the pod before it's ready, the seeds won't be ripe.
Then, we just hold the end and strip off the seeds. We're left with the not-yet-fluffy fluff in one hand, and the seeds in the other (or generally in a paper bag).
If we don't get to them before they're beginning to get fluffy, we just enjoy the fluff and collect the seeds anyway. It's just a little more of a challenge to separate the seeds from the fluff.
If you're not going to be sowing the seeds right away, store them in a paper envelope or bag, not plastic.
Growing Milkweed from Seed Outside
The easiest way is to sprinkle some seeds around in the fall after a killing frost and wait for spring. The seeds experience winter and know when it's time to get growing in spring.
This is probably the easiest method, but it's hard to remember to look for them in the spring and to recognize the seedlings as they emerge.
Of course, we do get a few seedlings popping up on their own around the yard, the seeds having been scattered by the wind the previous fall. Unlike some plants (e.g. jewelweed), though, swamp milkweed seedlings aren't a problem since there never seems to be very many. If they do pop up where we don't want them, we just pull them out, transplant them elsewhere, or pot them up to give away. The more people growing milkweeds the better!