Milkweed (Plants for Pollinators Part 1)
Updated: Feb 20, 2020
This is the first blog post in a series I am writing about plants you can grow in your garden to help pollinators. As beneficial insect populations are declining, with the first bee species ever to be listed as endangered, it is important now more than ever to grow plants in our gardens that will promote biodiversity and help pollinators. Each week I will write about a different plant, including which pollinators the plant benefits, and instructions for how to grow the plant from seed.
Which pollinators does milkweed benefit?
Milkweed is the only host plant for the caterpillar of the monarch butterfly. The caterpillars eat milkweed, and no other plants, meaning that without milkweed to feed on, this species of butterfly would become extinct. The flowers of the milkweed plant support a variety of other pollinators. On our farm, honey bees from the hives of our neighbor across the street flock to the milkweed flowers. A colorful parade of other butterflies fluttering their silken wings arrive, such as yellow tiger swallowtails and blue tropical checkered skippers. Many species of native bees and other butterflies feed on the nectar from the milkweed flowers. These bees and butterflies are vital to pollinating our vegetable crops, and to supporting the overall ecosystem. Humans can also eat the young milkweed sprouts in early spring, and the unopened flower buds. Please exercise caution in ensuring correct identification, and harvest the milkweed in a sustainable manner, leaving some for the pollinators. Be sure to cook all milkweed thoroughly before eating.
Honey bees visiting milkweed flowers at Sterling Organic Farm.
Why is it important for home gardeners to plant milkweed?
Milkweed populations in the northeastern United States have plummeted. Milkweed thrives in full sun to partial shade, and more of the land in this region is now shaded by forests than it has ever been in thousands of years. Prior to the arrival of the Europeans, Native Americans managed east coast forests by burning and cutting down trees so that the forest was open and full of light, ideal for milkweed to thrive. European settlers converted the landscape to farms, and at one point almost all of New England was farmland. Milkweed also thrives on the edges of small organic farms. Our farm is full of it. Eventually the expansion into better farmland in the more western parts of the country meant that most New England farms were abandoned and became densely shaded forest. You can still see the stone walls of the old abandoned farms criss-crossing the woods. Milkweed no longer grows in these areas due to the shade.
You can help restore milkweed habitat by planting some in your yard. Simply converting a small part of your lawn or garden to native, pollinator-friendly plants, such as milkweed, can have a huge impact on hungry pollinators looking for food. Milkweed seeds can be planted in the fall, the winter, the spring and early summer. Depending on the time of year, the method you will use to get your milkweed sprouts will vary. Read on to learn about how to obtain milkweed seeds, and the three methods for how to grow them.
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Obtaining milkweed seeds
Make sure to only grow species of milkweed that are native to your area, to best benefit native pollinators. There is some evidence to suggest that tropical milkweed, when grown in northern regions, interferes with the southern migration of monarch butterflies by blooming later in the season. One of the best ways to be sure you have native milkweed seeds is to look for the dried seed pods in the fall in meadows and along the edges of fields on organic farms. Take a small amount of the available seeds and leave enough seeds behind for the milkweed to regenerate itself. If you are unable to collect seeds, you can use the Xerces Society Milkweed Seed Finder website to help you obtain the correct milkweed seeds for your region. Once you have your milkweed seeds, they will require a period of cold temperature in damp conditions in order for them to sprout and grow into milkweed plants. There are three ways to achieve this.
Dried milkweed seed pod at Sterling Organic Farm. It is important to monitor your milkweed pods in the late summer and early fall to harvest seed at the correct stage. You want to harvest when the pods are no longer green, but before the pods burst and scatter their seeds to the wind.
Planting milkweed - method 1, refrigerator sowing for late winter through summer
The first method is to use your refrigerator as a source of the cold temperatures. The advantages of this method are that it is very reliable, and you can start milkweed seeds this way at almost any time of the year, as it does not rely on cold outdoor temperatures to prime the seeds. I started swamp milkweed with this method last spring and had 90% germination of the seeds. You can start the milkweed seeds this way in late winter, growing the seedlings in a sunny window until the last frost is past and then planting out in your garden. You can use this method in the spring, and also in the early summer. The latest you can use this method is 90 days before the first fall frost, to give the milkweed enough time to put on enough growth to be able to survive the winter. In our region, this means the latest date we can start milkweed seeds is July 10.
Materials you will need, in addition to the milkweed seeds, are a microwave-safe container that you will no longer be using to store food, and one half cup of damp potting soil. An old plastic take-out tub works great for this. Microwave the potting soil in the covered container until the soil is steaming hot, in order to kill algae and bacteria. Allow the soil to cool to room temperature, then mix the milkweed seeds into the soil. Keep the sealed container of damp soil mixed with milkweed seeds in the refrigerator for 40 days. You might want to label this container DO NOT EAT. You can then spread out this soil in your garden, if it is past the last frost date, or on the tops of pots of soil in a sunny window. Once the milkweed plants have four leaves, transplant them to one foot apart.
Planting milkweed - method 2, fall sowing
This method is simplest, but can be somewhat unreliable. Sow the milkweed seeds in your garden in the fall. They will be primed to sprout in the spring by the cold temperatures over the winter. When using this method, it is best to sow the seeds heavily. Some seeds will be eaten by hungry mice and other critters, while others will get washed away during heavy rain or by snow melt. With luck, you will have a nice crop of milkweed plants come spring.
Planting milkweed - method 3, winter sowing
Winter sowing works well for milkweed, as well as other seeds of native perennial plants that require cold temperatures to sprout. Winter sowing combines the protected enclosure from the first method, and the natural cold of winter weather of the second method. Winter sowing can be done any time after the winter solstice. Remember that milkweed needs at least 40 days of cold temperatures to sprout, so don’t wait too long to start your winter sowing. You will need a clear or translucent plastic container that can hold at least three inches of soil and still have room in the top of the plant to grow upwards. Milk jugs are an excellent container, as are three liter soda bottles, plastic vinegar jugs, and plastic kitty litter tubs. Cut the container nearly in half, leaving one inch attached as a hinge. Punch holes in the bottom of the container for drainage. Fill the bottom half of the container with potting soil, and plant the milkweed seeds one quarter inch deep into the soil. Seal the containers closed with duct tape, and leave outside all winter. Make sure to take the cap off of the container to allow rain and snow in, and to let excess heat out on sunny days. Check occasionally to make sure they are not too dried out, and add water as needed. Transplant your milkweed plants one foot apart in the garden once all danger of frost is past.
Winter sowing is used at Sterling Organic Farm to start many of our flowers
Spread the word
Please share this blog post to help more people learn how easy it is to grow milkweed from seed, and how vitally important it is for all landowners to devote a portion of their land to milkweed and other native plants that help pollinators. There are buttons to share to social media below, at the bottom of this page. You can also show your love for the pollinators to the world with our Bee Nice to Bees tote bag. We are using all the profits from the sales of our merchandise to restore and revitalize the oldest organic farm in Eastern CT. Certified organic farms like ours use no pesticides that harm bees and butterflies.
The more flower subscriptions we sell, the more flowers we plant, and the more the bees benefit. If you cannot grow your own flowers in your yard, consider buying ours. Shop here for flower subscriptions.
Stay tuned for next week's post about a different pollinator friendly plant, one that is super easy to grow and has gorgeous blooms!