The monarch population coming out of Mexico as of March 2010 is the lowest ever. To rebuild the population, we need to plant lots of milkweed for them to lay their eggs on. Help create a healthy crop of caterpillars this year by growing milkweed!

Here are some tips on growing milkweed from seed. (Contact us if you need seeds.)

Swamp milkweed (Asclepias incarnata)

Contrary to its name, swamp milkweed doesn't have to be grown in a swamp. Medium to wet soil (even in the shallow edges of a pond) will work fine. It will grow in sun or partial shade.

Here are some tips on growing milkweed from seed:

• In the fall, you can just sprinkle seeds in your garden and wait for spring! This is easy, but it's not as reliable as starting them inside.
• If you're planting seeds in the spring, it's a good idea to cold stratify them. This simply means that you put them in a moist paper towel in a plastic bag in the refrigerator for 3 - 6 weeks. You're making them think they're going through winter. Here's what they look like before going into the plastic bag and into the refrigerator.
• For a faster start, you can start them indoors 6 weeks before the last frost date, growing them under fluorescent lights. If you're cold stratifying them first, this would mean you could start put them in the refrigerator as early as mid-February, so you can plant the seeds in late March. They'll start germinating about two weeks after planting.
  Don't worry if you weren't able to start them this soon this year. Remember, these are perennials. Although it's nice to have good size plants to set out in the spring, they'll be coming back year after year, so getting off to a slower start the first year isn't a problem.
  
  Notice the small white dot on the underside of the top right leaf. That's the monarch egg! They'll lay eggs on even the smallest plants, though I doubt this tiny plant will be able to keep up with the caterpillar's appetite, so it's much better to have a lot of larger plants.
  
• If you don't want to cold stratify, try soaking the seeds in warm water for 24 hours before planting. In our experience, it didn't seem to be much better than just planting the seeds, though. And though some recommend that the cold stratified seeds also be soaked in warm water for 24 hours, it didn't make a difference in our results, although it didn't hurt them either.
  
• Cover the seeds with about 1/4" of soil.
• Guess which flat in the photo below has the seeds that were cold stratified! Virtually every seed came up, and much sooner than the seeds that were simply planted or soaked. (Half the seeds in the flat on the left were soaked and half were simply planted with no special treatment other than being on the cold porch all winter. The flat on the right were the cold-stratified seeds.)
  

Multiply by dividing

Although it doesn't seem to be an "officially" recommended way to get more swamp milkweed plants, we've been successful in dividing them. (NOTE: This would NOT apply to butterfly weed (A. tuberosa) since it has a long taproot.)

Note that in the photos, the separate plants are being gently teased apart. One plant became four! These separate parts seem to grow very well. Also note how the roots are growing. Unlike common milkweed (A. syriaca), swamp milkweed does not spread underground, so it's a much more well-behaved flower garden plant.

The plant to be divided. Each stem will be a new plant.

The plant is dug up.

The separate plants are being gently teased apart, letting their roots untangle as you gently pull.

Voila! Four plants where there had been one - three large ones and one small one (in the upper right). Generally these small ones will grow fine, too.

Don't think it's dead

Milkweed doesn't start growing as early as other plants in the spring, so you may think it didn't make it through the winter. Not so! It generally survives the winter quite well - it's just a little lazy coming up. The photo was taken on May 8, at a time when many other plants had been up and growing for a while. One trick is to leave at least some of the stalk (as seen in the photo) throughout the winter as a marker so you'll know where it should be coming up in the spring.