eXtension

Milkweed Help!

Asked July 3, 2019, 11:47 AM EDT

Hello!
I am having issues with some Milkweed plants we have. They are planted in a spot where they receive full sun from about noon on. The plants were all purchased from a local nursery just a few weeks ago, and were planted right away. We planted them in a mix of topsoil and organic compost/garden soil and about a week later covered with mulch. In the evening they were looking a bit sad and droopy along with the Tickseed and Calamint I planted them with. Once they were watered, they perked right up.

Then I noticed my 2 of 4 of my Cinderella Milkweed (same as Swamp Milkweed?) started getting some yellow leaves, very fragile to the touch, and then they fell off starting from the bottom of the plant up. I have 3 of what I think is common Milkweed and it's doing just fine. I can't figure it out. Please help a girl (and her milkweed) out!

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Allegheny County Pennsylvania

3 Responses

Ascelpias incarnata wants to be in full sun all day. It grows naturally in soil near water and in poor soil. I've grown several species of milkweed in my garden, and find the plant difficult to manage in a cultivated border. Often it seeds itself elsewhere on my landscape.
In nature swamp milkweed is often found in open meadows where it spreads by underground tubers. Because it is a wild plant, it is specifically adapted to its native conditions and may not thrive in your garden bed. One thing you can try is lifting the plant and putting it in a pot with a very lean soil mixture with a low amount of organic matter. Then make sure it gets morning sun as well as afternoon sun.

Thank you!
Are there specific varieties of milkweed you would recommend for this spot in our garden to replace the swamp milkweed when we move them?

I've tried many different approaches to growing milkweed at my house, and the plant has been difficult. The best solution I found is to grow tropical milkweed (Asclepias curassavica) as an annual. It does fine in garden borders and it provides plenty of seeds for you to plant next year. Also the flowers are attractive and the plant looks good in garden borders.

The Monarchs are attracted to tropical milkweed because the leaves are tender. Here is a link to a butterfly website that recommends tropical milkweed. https://nababutterfly.com/tropical-milkweed/

Seeds are for sale at seed companies on the internet. If you want to save seeds in the future, wait until the pods open and put a plastic bag over the pod before removing it from the plant. That saves having the seeds fly all over. Because the plant is tropical, it won't come back next year and the seeds can't survive the winter outside. You'll either need to buy each growing season, or save seeds.
If you save seeds, store them in a paper envelope, not a plastic bag. Keep them cool and dry, but don't refrigerate them. I have an area in my husband's workshop that is perfect in my case.
In the spring, take off the white silk and plant the seeds in a seed starting mix. Then transplant into the garden. I always grow extra so I can donate them to the plant sale at my nature center.