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Butterfly Weed
Asclepias tuberosa
Also comes in yellow and red.
Butterfly Weed blooms from June through August.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Butterfly Weed
Plant it in full sun. It prefers low water. It is hardy in USDA zones 3–9. Expect it to reach about 24 in tall and 16 in wide at maturity, in roughly 2 years (not yet checked).
What was checked
Mature height and spread, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not, and each fact above says which. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.
When to plant Butterfly Weed
Plant Butterfly Weed in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 6, the middle of its hardy zones 3 to 9, spring means March to May and fall means August or September. Once settled, it blooms from June to August.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 6, the middle of this plant's hardy range, start with zone 6 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Butterfly Weed get?
24 intall5 ft 7 inan adult16 inwideSee Butterfly Weed in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
How far apart to plant Butterfly Weed
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Butterfly Weed about 16 in apart, center to center, so each plant has room to reach its full width.
Add Butterfly Weed to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.
Where these facts come from
Butterfly Weed's height, spread, hardiness zones, sun and trait tags were checked against 10 published sources on July 30, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.
- Missouri Botanical GardenPlant Finderheight, spread, hardiness zones, sun, years to mature size and trait tags
- NC State ExtensionPlant Toolboxheight, spread, hardiness zones, sun, years to mature size and trait tags
- University of Wisconsin HorticultureUniversity of Wisconsin-Madison Division of Extension, Wisconsin Horti...height, spread, hardiness zones, sun, years to mature size and trait tags
- New Moon Nurseryheight, spread, hardiness zones, sun and trait tags
- Prairie Moon Nurseryheight, hardiness zones, sun, years to mature size and trait tags
- RHSRoyal Horticultural Societyheight, spread, sun and years to mature size
- Lady Bird Johnson Wildflower Centerheight, sun and trait tags
- University of Maryland ExtensionHome and Garden Information Centerheight, sun and trait tags
- Missouri Department of ConservationField Guideheight
- Native Plant Trust (Go Botany)Native Plant Trust GoBotanyheight
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Butterfly Weed
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note. A note reports what its source says; where that differs from a fact above, the fact above is this entry's stored value, and its mark says whether it has been checked.
Safety
Toxic to dogs, cats and horses: all parts carry cardiac glycosides (cardenolides), and the sap can irritate skin on contact. per ASPCA and NC State
Worth knowing
One deep, woody taproot explains its quirks: it stores deep moisture (great drought tolerance), resents being moved, is slow to establish, and emerges late each spring. per NC State
A clump, not a runner
Unlike common milkweed, which runs by rhizomes, butterfly weed stays a tidy, upright clump from its single taproot. The well-mannered milkweed for a border. per NC State and Wisconsin
Monarch host and nectar source
Monarch caterpillars eat the leaves, and the flowers pour out nectar for butterflies, hummingbirds and bees. A high-value pollinator plant on both counts. per NC State and Missouri Botanical
Oleander aphids, its signature pest
Bright yellow oleander aphids cluster on stems and buds. Hose them off and let lady beetles and lacewings handle the rest; don't spray, it kills monarch caterpillars. per Colorado State and NC State
Deer leave it alone
Deer leave it alone, put off by the bitter, toxic milkweed foliage. Rabbits, though, may still nibble at it. per NC State and Wisconsin
What pairs well with Butterfly Weed
Good companions share its growing conditions and add something it lacks: an earlier or later bloom, a lower carpet in front, or structure through winter.
Goldenrod
Shares full sun and low water; overlaps, then carries the display into mid fall; both are strong pollinator plants; its seed heads stand through winter, for structure and the birds.
Rock Cress
Shares full sun and low water; blooms in mid spring, before this one opens; both offer pollinator forage, in different months; evergreen, so the bed keeps its shape through winter.
Aster
Shares full sun and low to moderate water; blooms in early fall as this one finishes; both are strong pollinator plants, and they feed in different months; its seed heads stand through winter, for structure and the birds.
Switchgrass
Shares full sun and low water; overlaps, then carries the display into mid fall; both are strong pollinator plants; its seed heads stand through winter, for structure and the birds.
Rosemary
Shares full sun and low water; blooms in early spring, before this one opens; both are strong pollinator plants, and they feed in different months; evergreen, so the bed keeps its shape through winter; they only overlap in zones 8 to 9.
Wisteria
Shares full sun and low to moderate water; blooms in mid spring, before this one opens; both are strong pollinator plants, and they feed in different months; purple against orange, for contrast.
Little Bluestem
Shares full sun and low water; overlaps, then carries the display into early fall; its seed heads stand through winter, for structure and the birds; taller at 3.5 ft, for the layer behind it.
Fountain Grass
Shares full sun and low water; overlaps, then carries the display into mid fall; its seed heads stand through winter, for structure and the birds; taller at 3.5 ft, for the layer behind it.
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Design a garden with this
Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.