In 2014, I came across one of the most clever uses of a hashtag I’ve seen on social media: #GotMilkweed. The hashtag was part of a campaign launched by the David Suzuki Foundation that aimed to create a monarch butterfly corridor in Toronto. (For readers who live in the U.S. and abroad, David Suzuki is a prominent scientist and environmentalist here in Canada.)
The statistics are grim. Scientists have been reporting staggeringly low numbers of monarch butterflies that migrated to Mexico, partly due to the eradication of milkweed across North America. The milkweed plant is not only an important food source for monarch caterpillars, it’s the only plant on which a monarch butterfly will lay its eggs. (2016 update: A World Wildlife Fund survey suggests “migratory monarchs are rebounding—but with a long road ahead.”)
In the last couple of years, scientists have been encouraging gardeners to plant milkweed to help the monarch butterfly population. I planted some in my garden and asked wildflower guru Miriam Goldberger, author of Taming Wildflowers (St. Lynn’s Press, 2014) for some advice.
A few tips for purchasing and planting milkweed
“It’s unfortunate that such a beautiful and important plant in our North American ecosystem is named a weed,” says Miriam. Common milkweed (Asclepias syriaca) is the source of the plant’s bad reputation—it’s quite invasive. Here in Canada, it also used to be on the Ministry of Natural Resources’ noxious weeds list.
The good news is there are other types of milkweed that don’t spread. “Monarchs will also enjoy red milkweed (Asclepias incarnata) and butterflyweed (Asclepias tuberosa),” says Miriam. “Both of these are host plants for the adult monarchs as they lay eggs, and as food source hosts for the larvae (caterpillars). These two alternatives do not spread by rhizomes and are employed by monarchs just as often as the common milkweed.”
Miriam says that red milkweed will grow in any soil type, but it prefers medium to moist soils. It likes full sun (though it will tolerate a bit of shade). “Butterflyweed will also tolerate some shade, but is a bit more picky about its soil type, preferring sand or loam. Dry to medium soils are preferred,” she says.
And, you can still plant common milkweed, says Miriam, especially if you have dry, clay soil. You should plant it with a combination of other native flowers and grasses that take up the various levels of soil, she warns. “Common milkweed spreads by rhizomes (underground runners or roots) which is why it can be such an aggressive spreader. By planting it within a fairly dense planting of other native species, you leave minimal room for the rhizomes to travel.”
Miriam says liatris, goldenrod and asters are other forms of monarch nutrition that you can add to your garden.
Sadly, in the last few years I haven’t seen many monarch butterflies flitting throughout in my garden. I’ve spotted a few other types, especially around my buddleia, but I want to make sure the monarchs find a welcoming spot in my garden, too. I eagerly spread the #GotMilkweed message so other gardeners could add it to their must-plant lists. “Anything that brings forward the issue of native pollinator health is a good thing,” agreed Miriam, who says the monarch butterfly issue is coming to light, largely due to David Suzuki and his team’s efforts. “He is raising awareness in a way that only David Suzuki can and it’s proving to be a positive step forward.”
Where to buy milkweed
A local native plant sale is a good place to begin your hunt for milkweed. Ask your local nursery manager if the store will be carrying any native varieties this spring. Miriam sells seeds through her Wildflower Farm website. In Nova Scotia, Baldwin Nurseries sells plants. Botanical Interests offers Asclepias speciosa.
Tips for saving and growing your own milkweed seeds are found in this video.
Main image (red milkweed) courtesy of Miriam Goldberger