Milkweed and Monarch Butterflies: Why This Plant Matters

During the bleak of winter, we miss the flora of the farm most of all. Chesterhaven Beach Farm is covered with acres of wildflowers, native grasses, and trees, a little haven for the bees. One plant in particular stands out from the crowd: milkweed. It is the single most important plant for monarch butterflies, and it happens to grow beautifully here on Maryland’s Eastern Shore.

Blooming from early to late summer, milkweed grows wild across our property, filling the landscape with seas of mauve and pink pompom–esque blooms. To supplement what nature has given us, we have added our own plantings of orange butterfly weed around the farm. When these plants come into bloom, they draw in every kind of pollinator you can imagine. You would not believe the swarms of bees that surround the flowers. It is almost unbelievable.

What Is Milkweed?

Milkweed is the common name for plants in the genus Asclepias, a group of hardy native perennials with more than 70 species across the United States. Despite the name, it is not a weed in the nuisance sense at all. It is one of the most valuable plants you can add to a pollinator garden.

The plant gets its name from the milky sap that oozes from the leaves and stems when they are broken. That sap contains cardenolides, naturally occurring compounds that can be toxic if ingested by people or pets, and it may cause skin irritation in sensitive individuals. We suggest wearing gloves when gardening around milkweed. After the flowers fade, the plants form their trademark seedpods, which eventually burst and release silky tufts that carry the seeds on the wind. During World War II, that floss was actually collected as a substitute for kapok and used to fill life jackets, a wonderful bit of history for such an unassuming plant.

Why Milkweed Matters for Monarch Butterflies

Here is the reason milkweed belongs in every garden that can host it: it is the only plant monarch caterpillars can eat. Monarchs lay their eggs exclusively on milkweed, and the hatching caterpillars feed on nothing else. Without milkweed, there are no monarchs. It really is that simple.

The connection runs deeper still. As the caterpillars feed, they take in those bitter cardenolides from the sap, which makes both the caterpillars and the adult butterflies unappealing to many predators. The plant that feeds them also helps protect them. Adult monarchs, by contrast, sip nectar from a wide range of blooms, so a healthy monarch habitat pairs milkweed with other nectar plants for the grown butterflies to feed on.

Monarch numbers have fallen sharply in recent decades, driven largely by the loss of milkweed across farmland and open space. Planting milkweed is one of the most direct things a home gardener can do to help. If you want to see which butterflies already visit your area, our guide to the butterflies of Maryland is a lovely place to start.

Common Types of Milkweed

Not all milkweed is the same, and choosing a species suited to your soil and light makes all the difference. A few reliable, widely available options include:

• Common milkweed (Asclepias syriaca): The classic roadside milkweed with fragrant pink blooms. It spreads readily by underground roots, so give it room.
• Butterfly weed (Asclepias tuberosa): A shorter, well-behaved species with showy orange and yellow blossoms. It is a favorite for tidy garden beds and the one we plant most around the farm.
• Swamp milkweed (Asclepias incarnata): Loves damp, sunny spots and produces clusters of rosy-pink flowers, perfect for a rain garden or a low, wet corner of the yard.

Whichever you choose, plant a native species suited to your region and plant it in clumps so caterpillars can move easily from leaf to leaf. For a fuller planting plan, see our guide to planting a pollinator garden, and our roundup of the best native Maryland wildflowers for companion blooms.

Milkweed as a Pollinator Plant

Milkweed offers nectar to pollinators from the moment it opens right up until the flowers fade. Its pollination is genuinely strange, in the best way. On most plants, pollen forms loose individual grains that get dusted from bloom to bloom. On milkweed, the pollen is packed into whole clumps called pollinia that get carried off in one piece. Because of this, butterflies are not especially effective pollinators of milkweed. The way they feed simply does not move much pollen. Hummingbirds and hummingbird moths visit the nectar too, though they do not pollinate it well either. Bees are the real workhorses here. They crawl right into the flowers and pick up those clumps of pollen as they go.

All of that foraging activity is part of what makes wildflower honey possible. The same milkweed and native blooms that feed our bees each summer help shape the flavor and character of our Eastern Shore Honey, which tastes like the season and the land it came from. If you are curious about how nectar becomes honey, our explainer on pollination breaks it down.

Growing Milkweed on the Eastern Shore

Milkweed is one of those plants that only seems to grow with lots of friends, and honestly, the more the merrier. We love that it asks almost nothing of us. It needs no fussing, and it comes back year after year, stronger than the season before. Most native milkweeds want full sun and well-drained soil, and once established they are wonderfully drought tolerant.

If you already have milkweed in your yard, our best advice is to let it bee. The flowers are beautiful and fragrant, the shrubby form adds real dimension to a garden bed, and the dark, faintly velvety leaves balance out brighter flowers around them. Leave it to bloom and you will very likely fall for it the way we have. Want to see how it fits into the bigger picture on our farm? Come meet the farm.