Working with Milkweed and Monarchs

Monarch Butterfly (photo by Jim Gallion)

Monarch Butterfly (photo by Jim Gallion)

“Have you seen any this year?” My fellow gardening friends and I have been asking each other this question. Monarchs have been in the news: their numbers are down, WAY down, and we are now grappling with the possibility that this once familiar emblem of adaptation and co-evolution may, under our watch, become extinct and unknown to future generations.

The monarch caterpillar depends on the availability of milkweed for survival. And we have recently learned that the easiest of the milkweeds to incorporate into a garden setting, ironically named “butterfly milkweed” (Asclepias tuberosa) may actually be the least helpful of the milkweeds for the monarch.

Common milkweed blossoms (photo by Jim Gallion)

Common milkweed blossoms (photo by Jim Gallion)

Although it is shorter, beautifully bright orange, and has a bloom that turns upward and is easier to incorporate in ways we are used to seeing plants in a garden setting, its sap is less milky and contains less of the substance that protects monarch caterpillars from birds. This means that caterpillars chewing on orange-blooming butterfly milkweed will enjoy less of that famous protection that every child (I hope) still learns about in school.

In spite of this, I’m not ready to rip out all the butterfly milkweed in the gardens I’m responsible for. The flowers are still an important source of nectar for adult butterflies, and this too is significant. But I am on a quest to find more ways to successfully incorporate other milkweeds into home landscapes.

Monarch and butterfly weed (photo by Jim Gallion)

Monarch and butterfly weed (photo by Jim Gallion)

Two other easy-to-grow milkweeds that should be occurring in our area in abundance—but sadly are no longer—are swamp milkweed and common milkweed.

Swamp Milkweed, Asclepias incarnata, is found in damp places but also adapts well to normal garden soil and is even drought tolerant once established. Like many low-oxygen adapted plants, it can handle clay soil. It grows 4-6’ tall in full or part sun, and blooms reddish pink in May or June.

Common Milkweed, Asclepias syriaca, prefers drier, sandier soils and requires full sun. It blooms pale purple between May and August, and also reaches a height of 4-6’.

Both are tall, bold-looking, sturdy plants that are easy to enjoy when in bloom—particularly since the beautiful, nectar-rich flowers will be covered with activity.

Swamp milkweed blossom with bees (photo by Kai Hagen)

Swamp milkweed blossom with bees (photo by Kai Hagen)

The tricky part comes later on, since they sometimes go brown early in the season. And if you are a successful monarch gardener, the leaves will be eaten away—often down to the stem! The pods are a very interesting feature, eventually and dramatically releasing their white-parachuted seeds out into the world. But even this could be a challenging development in some neighborhood contexts…

Here are some strategies that I’m experimenting with, and I look forward to hearing about yours. I hope in future years to share photos of the results of each of these.

Monarch caterpillar on milkweed leaf (photo by Jim Gallion)

Monarch caterpillar on milkweed leaf (photo by Jim Gallion)

1. Monarch Meadow. We recently planted a moderately steep, sunny slope of very poor soil with drifts of common milkweed and swamp milkweed plugs. We are hoping to attract monarchs to an area they may not have been to in a while, so we planted 64 plugs of each of the two species.

Since this slope is the primary view from the back of a home, I also wanted to provide something “prettier” to look at when milkweed is finishing out its season and may be looking a bit tired. So in front of each drift, or sometimes mixed into it, we planted New England asters in gallon containers (20 of these). In previous years when Monarchs were more numerous, I used to see migrating flocks of them nectaring hungrily on late-season asters. Such a fantastic sight!

This fall we will also be adding Beardstem (andropogon virginicus), a warm-season grass that likes poor, dry soil and is one of the shorter meadow grasses at 2-3’ high. The whole area is mulched to give the plants’ roots time to develop a starter foothold against the drought they will soon have to endure. The mulch is for installation only and will not be replenished every year.

2. Secret Monarch Munchies. This strategy puts a swath of milkweed at the back of a deep bed. They are behind shorter plants that bloom later in the season and can distract the eye away from all those munched-away leaves and gaunt, dry-looking stems that can happen.

A similar strategy works well for the giant, beautiful Joe Pye, which is another important nectar plant for monarchs and many other butterflies. So plant both of these tall plants in the back of a deep (at least 3-4 feet) perennial bed, then plant appropriate late-summer and early fall blooming plants toward the front.

3. Make No Apologies. Designate a good corner of your backyard to be the local Monarch Mecca. Plant it with milkweed and select other native perennials so that the adult butterflies have a good food source throughout the entire growing season. Consider putting in a few large stones with rough surfaces, and water the stones regularly so that butterflies can “puddle”.

Then put up a sign or invite the curious to come out and look for indications of monarchs: challenge them to find munched leaves, frass, even a chrysalis.. . And we hope, of course, the beautiful adult monarch butterflies as well, in ever recovering numbers.


Have you been seeing any Monarch butterflies this year? Please visit this conversation on Facebook to let us know, or to share any thoughts about monarchs and milkweeds with Chris: https://www.facebook.com/EnvisionFrederickCounty/posts/560710767333736

Milkweed seed pods (photo by Kai Hagen)

Milkweed seed pods (photo by Kai Hagen)