June 23, 2025
Grow Milkweed and Host Plants for Butterflies!
When you think of butterflies, you probably picture them fluttering gracefully from flower to flower. But did you know that before they become beautiful butterflies, caterpillars are some of the pickiest eaters in the garden?
Unlike adult butterflies, who sip nectar from many kinds of blooms, caterpillars often rely on specific host plants — special plants that provide the exact food young caterpillars need to grow and thrive. Without these host plants, we wouldn’t have butterflies at all!
One of the best examples is milkweed, the essential host plant for monarch butterflies. Monarch caterpillars can’t survive without it. Female monarchs lay their eggs exclusively on milkweed because their hungry caterpillars will eat nothing else. This unique relationship has been shaped by millions of years of coevolution.
What Makes Milkweed So Special?
Milkweed isn’t just a food source; it’s also a built-in defense system. The leaves contain natural chemicals called cardenolides (a type of toxin) that the caterpillars store in their bodies. This makes both the caterpillars and the adult monarch butterflies distasteful to predators like birds. So, milkweed offers both nourishment and protection — a true multitasker in the garden!
Host Plants: Nature’s Baby Food
Monarchs aren’t alone in their picky eating habits. Black swallowtail caterpillars need dill, fennel, or parsley. Spicebush swallowtails rely on spicebush and sassafras. Pipevine swallowtails need — you guessed it — pipevine!
Each butterfly species has its own menu of acceptable host plants, and without these plants in our gardens, there’s nowhere for butterflies to raise their young. Nectar flowers feed the adults, but host plants feed the next generation.
Which Milkweed Should I Plant?
Not all milkweed is the same. Depending on your yard and local conditions, you’ll want to choose native varieties that thrive in Massachusetts:
- Common Milkweed (Asclepias syriaca): Great for sunny spots with room to spread.
- Swamp Milkweed (Asclepias incarnata): Prefers wetter soils — perfect for rain gardens.
- Butterfly Weed (Asclepias tuberosa): Compact and showy with bright orange blooms; loves dry, sunny spots.
Native milkweeds are low-maintenance and provide the best support for local monarchs.
Other Easy Host Plants for Butterflies
Dill (Anethum graveolens)
Want to attract even more butterflies? Add a mix of other native host plants:
- Parsley, dill, and fennel: Loved by black swallowtail caterpillars.
- Spicebush and sassafras: Hosts for spicebush swallowtails.
- Violets: Essential for fritillary butterflies.
- Birch or wild cherry trees: Provide food for tiger swallowtails.
- Willows: A favorite for mourning cloak butterflies.
How You Can Help
Planting milkweed is one of the best things you can do to support monarchs. There are many varieties — common milkweed, swamp milkweed, and butterfly weed are all native to many parts of North America and easy to grow.
In addition to milkweed, consider adding other host plants to your yard to attract a wider variety of butterflies. The more host plants you offer, the more caterpillars (and butterflies!) you’ll get to enjoy.
Ready to grow a butterfly-friendly garden? Stop by and explore our selection of milkweed and other host plants. Let’s turn your garden into a haven for caterpillars and the butterflies they become!
Interested in the Life Cycle of Monarch Butterflies? Check out our infographic here!