Milkweed For The Monarch Butterflies

During the summer, I often found the madman in the Milkweed patches. He would carefully examine each plant – turn over the leaves, look at the seed pods, shake his head: you know the drill. But he wasn’t out there practicing IPM (Integrated Pest Management) as described in this link, he was looking for signs of the Monarchs. We have never been good at finding the single eggs, but a chewed-off leaf edge really sticks out and we know that most likely a caterpillar is nearby.

Monarchs only lay their eggs on these plants – and the madman loves his Monarchs. If you love Monarchs, you also have to love Milkweed. You have probably heard about the plight of the Monarchs and how each of us can do a little bit to help this beautiful butterfly survive. Plant Milkweed, they all say. You see, Monarchs have an exclusive arrangement with Milkweed, but Milkweed doesn’t have an exclusive arrangement with Monarchs. Milkweed, being a native plant, supports a number of native insects.

Milkweed

Milkweed (Asclepias spp.) is a native of North America, ranging from Southern Canada to Central America. All Milkweeds support Monarchs – some are better at it than others, and you should never plant one species. The bad apple in this family is Tropical Milkweed (A. curassavicais). Most articles about Milkweed throw the warning about Tropical Milkweed at the end. But the madman thinks it should be brought to the front. Also known as Scarlet Milkweed, Blood Flower or Mexican Butterfly Weed, this species is native to the American tropics.

Trouble for Newbies

Newcomers to the world of gardening are attracted to this plant for its bright blooms. In Connecticut, gardeners grow it as an annual since it is not winter hardy, but in southern gardens, it is gaining popularity because it is easy to grow. This plant sometimes harbors OE (Ophryocystis elektroscirrha), a protozoan parasite that can damage Monarch populations. Infected Monarchs can’t develop correctly and have difficulty flying.

If this isn’t enough for you, A. curassavicais is a late bloomer and can sometimes tempt the Monarch to stay behind instead of making the trip to Mexico – the traditional overwintering habitat. The madman says, “Don’t plant this,” but there are plenty of others you can and should plant.

Natives

Here in Connecticut, there are ten native species of Asclepias, some of which are difficult to find. To establish a successful Monarch habitat, you should have at least two varieties plus other types of nectar plants like Zinnias, Cosmos and native wildflowers. According to Pamm Cooper, an educator from the Connecticut Home and Garden Center, the big three are Common Milkweed (A. syriaca), Swamp Milkweed (A. incarnate) and Butterfly Weed (A. tuberosa). All are readily available and easy to grow. Fall is the time to plant the seeds.

During a Master Gardener workday at the Haddam Garden, a fellow Master Gardener informed the madman that Milkweed was a weed she wouldn’t plant in her perennial beds because it was too aggressive. She must have been talking about Common Milkweed, the most aggressive of the three.

Common Milkweed

A.syriaca is the plant most people associate with the term Milkweed. Its light pink to purple flowers are delightfully fragrant and last four to six weeks in summer. A vigorous grower that will reach 5’ in height, Common Milkweed will produce large colonies over time. Colonies are formed when its aggressive rhizomes are allowed to spread far and wide. Seed pods are 3-4 inches long and are starting to ripen now. When ready, they split releasing tons of feathery seeds the wind carries off. The madman understands why you may not want to have this plant growing in your formal Rose Garden, but, surely, he says, “You must have a spot in the back where nothing else grows. That spot is perfect.”

Swamp Milkweed

A less aggressive variety is Swamp Milkweed (A. incarnata), but as the name implies, it’s a little fussier about its environment, preferring a bit of moisture. In the wild, it is often found at the edge of bodies of water or along ditches. It thrives in mucky, clay soils but has done well in my back garden bed. Although you won’t wage a battle with aggressive behavior, you will have to fight aphids. Hand picking or soapy water works well.

The rose-colored flowers of A. incarnata are rather fragrant, attracting a variety of pollinators. They bloom through mid-summer. I have found a white cultivar of Swamp Milkweed that I plan to add to the edge of my Moon Garden this fall.

Butterfly Weed

The third variety of Milkweed recommended for Connecticut gardens is Butterfly Weed (A. tuberosa). This 3-ft., bushy shrub is slow to establish from seed, taking up to 3 years to bloom. Although tolerant of any soil, A. tuberosa needs to be in full sun to thrive. With its long taproot, Butterfly Weed doesn’t transplant well, but its showy, prolific blooms last from June to August and are often called “pollinator magnets.”

Growing Milkweed

As we’ve said, growing Milkweed is fairly easy, and now is the time to begin preparing your beds and looking for seeds. If, like us, you are gardening for the wildlife, you need this plant. One source that I use is Prairie Moon Nursery because they have a good selection. Since Milkweed seeds need to be cold- stratified (put in cold ground) for 30-60 days, fall is the best time to plant them. We like to plant after the last fall frost.

Choose a nice sunny location. Rake the soil to clear any rocks or weeds, then water thoroughly. Although the madman likes to broadcast the seeds and cover with ¼” of soil, you may want to be a little neater. Plant the seeds about 6” apart and ½” deep in rows or grids. Cover with moist soil. Water again and wait for spring. Remember to mark your planting areas because some varieties are late sprouters.

Oleander Aphid

Asclepsias are relatively pest-free. That being said we have come across a couple of pests we’d like to share with you. First is the Oleander aphid (Aphis nerii), a bright orange sucker that we find on the stems of Swamp Milkweed. From what we’ve read, everyone who grows Milkweed will eventually find these aphids. Originally from the Mediterranean, they have found their way here thanks to inadvertent importation. The madman says his Oleander plants were not the source. We control ours easily with hand-picking.

Milkweed Bug

Our other pest is the large Milkweed bug (Oncopeltus fasciatus), a rather colorful red and black insect that feeds on the seeds. One source suggests that they keep the Milkweed in check by devouring seeds. If they get too numerous, we just pick them off. Remember, you shouldn’t be spraying your Milkweed with anything but water. Even that may knock off a tiny Monarch egg or instar, so be careful – we need all the Monarchs we can get.

In July 2022, the International Union for Conservation of Nature (IUCN) classified the migratory Monarch as endangered, citing a large decline in the Monarch butterfly’s population over the last decade. But take heart, some recent studies are showing an uptick in the number of migrating adults. See what we can accomplish when we all work together? Plant Milkweed. If you are looking for inspiration, check out this cool blog from the Smith-Boeth Monarch Waystation (#24758). Rick and Stephanie have some great photos of butterflies in their garden.

The madman toasts your efforts with his lemonade.