Milkweed Care: Native Asclepias for Monarch Habitat
Native Asclepias species — common, swamp, butterflyweed, and tropical milkweed — for monarch habitat, with species selection by zone, cold hardiness, and the tropical milkweed controversy.
Which milkweed species to grow
All Asclepias species support monarch larvae, but species vary significantly in habitat suitability, garden manners, and regional adaptability. Per Xerces Society, using "locally appropriate native milkweed species" provides the most ecological benefit and best garden performance.
Common milkweed (Asclepias syriaca)
The classic roadside milkweed of the eastern U.S. and Midwest. Zones 3–9. Spreads by rhizome and can be aggressive in small garden beds — better in meadow plantings, along fence lines, and in naturalized areas with room to run. Fragrant pink-purple globe flowers in June–July. Highly attractive to monarchs, bees, and many other pollinators. Per Penn State Extension, common milkweed is "one of the most important monarch plants in the northeast."
Butterflyweed (Asclepias tuberosa)
The showiest native milkweed in North American gardens. Brilliant orange (occasionally yellow) flowers, June–August, on compact plants 18–24 inches tall. Unlike common milkweed, it stays put — spreads slowly and is well-behaved in perennial borders. Zones 3–9. Requires well-drained soil and full sun; will not survive in wet or poorly drained soils. Drought-tolerant once established. Per University of Minnesota Extension, butterflyweed "tolerates drought but not wet soils."
One important note: A. tuberosa is slower to emerge in spring than other milkweed species. Gardeners frequently worry the plant has died over winter — patience is warranted. It often doesn't show new growth until mid-to-late May even in zone 7.
Swamp milkweed (Asclepias incarnata)
Pink or white flowers, June–August, on plants 3–4 feet tall. As the name suggests, this species tolerates wet soils and is excellent for rain gardens, pond margins, and moist areas where other milkweeds would fail. It also grows well in average to moist garden soil. Zones 3–8. Per Xerces Society, A. incarnata is "one of the most garden-friendly native milkweeds" because it tolerates a range of moisture conditions and stays clump-forming rather than spreading aggressively.
Tropical milkweed (Asclepias curassavica) — use with caution
Not native to North America. Available in garden centers as an annual or tender perennial, with vivid red-and-orange or yellow-and-orange flowers all season long. Very attractive to monarchs. However, per Xerces Society, tropical milkweed stays green through fall in frost-free zones 9–11, which disrupts monarch migration behavior — monarchs may stop migrating and accumulate on non-native milkweed rather than continuing to Mexican overwintering sites. It also harbors Ophryocystis elektroscirrha (OE), a debilitating protozoan parasite, at higher rates than native milkweed. If you grow tropical milkweed in zones 8 and above, cut it to the ground in October to force the plant into dormancy, which kills OE spores on the foliage and removes the green "rest stop" that disrupts migration. In zones 7 and below, hard frosts kill it annually, so the management concern is less acute.