Milkweed for Monarchs

Monarch butterflies have declined sharply over recent decades, driven by loss of habitat, herbicide use and extreme weather. Planting milkweed and other native nectar plants is one of the most direct ways to help, and the same plantings benefit water quality, soil and a host of other pollinators and wildlife.

Why milkweed matters

Milkweeds are the only plants monarch caterpillars can eat. Milkweed contains compounds called cardenolides, which caterpillars store in their bodies, making both caterpillars and adult butterflies distasteful to birds and other predators. Without milkweed, monarchs can’t reproduce.

More than milkweed

Adult monarchs need nectar throughout the season, and especially during their long fall migration of 2,500 miles or more from Canada and the northern United States to the mountains of central Mexico; western monarchs overwinter along the California coast. The annual round trip spans several generations of butterflies, so plantings that flower from spring through fall support each one along the way.

Good native nectar plants for monarchs include Black-Eyed Susan (Rudbeckia hirta), Dense Blazing Star (Liatris spicata), bee balms (Monarda), Purple Coneflower (Echinacea purpurea), Ox-Eye Sunflower (Heliopsis helianthoides), Lance-Leaved Coreopsis (Coreopsis lanceolata) and late-season asters and goldenrods.

Milkweeds for our region

Several native milkweeds suit different sites: Common Milkweed (Asclepias syriaca) for open, well-drained ground; Swamp Milkweed (Asclepias incarnata) for moist soils and wet meadows; and Butterflyweed (Asclepias tuberosa) for dry, sunny, sandy sites. Most milkweed seed needs a cold, moist period before it will germinate, so fall and dormant seedings work best; see the germination guide.