butterfly milkweed
Asclepias tuberosa · Asclepiadaceae
butterfly milkweed (Asclepias tuberosa) is a perennial herbaceous plant in the Asclepiadaceae family. It is native to North America. USDA records it as hardy in zone 3 and warmer, down to about -33°F.
At a glance
| Type | forb-herb USDA |
|---|---|
| Lifecycle | perennial USDA |
| Native status | native USDA |
| Mature height | 2 ft USDA |
| Light | full-sun USDA |
| Water need | low USDA |
| Growth rate | slow USDA |
| Soil pH | 4.8–6.8 USDA |
| Bloom | July USDA |
| Flower color | Orange USDA |
| Hardiness zones | 3 and warmer USDA |
| Guild layer | herb-layer Derived |
| Nursery availability | Routinely Available USDA |
USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.
Growing conditions
It needs full sun. USDA rates it as having low water needs once established. Its drought tolerance is rated high. It will not tolerate waterlogged soil — USDA rates its anaerobic tolerance as none. It is recorded on soils from pH 4.8 to 6.8 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 3.
Size and growth
At maturity it reaches about 2 ft, making it about knee height. It grows slowly.
Bloom period
USDA records a bloom period of July. Flowers are orange.
A flowering date, not a pollinator rating.
Foliage, flower and season
Summer foliage is green, coarse in texture. Its flowers are conspicuous. Its fruit or seed heads are conspicuous, extending interest past flowering. Its active growth period is spring and summer. USDA rates its lifespan as moderate.
What the site needs to provide
USDA records it across sites receiving 28 to 45 inches of annual precipitation. It needs at least 135 frost-free days to finish its season. It roots to at least 16 inches. Fertility requirement: low — no feeding needed on ordinary garden soil.
Propagating it
Propagate it from seed and container stock. USDA records no cold-stratification requirement, so seed should germinate without a chilling period. Its seed spreads at a slow rate. It does not spread vegetatively, so it will stay where you put it.
Resilience and wildlife
Browsing animals rate it barely palatable — the sourced basis for calling it deer-resistant. Its fire tolerance is rated high. Its growth form is recorded as multiple stem.
Role in a guild
Herb layer. In a layered planting this is the herbaceous middle — perennials and grasses that fill the space between ground cover and shrubs. The layer is derived by a fixed rule from growth habit and mature height.
Tags
Related plants
Others in Asclepias
- swamp milkweed Asclepias incarnata
- showy milkweed Asclepias speciosa
Similar role and hardiness
- common maidenhair Adiantum capillus-veneris
- winter bentgrass Agrostis hyemalis
- European water plantain Alisma plantago-aquatica
- American sloughgrass Beckmannia syzigachne
- slenderbeak sedge Carex athrostachya
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol ASTU, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.
- Quoted from USDA PLANTS: active growth period, Bloom, Bloom end, browse palatability, cold stratification, Drought tolerance, fall conspicuous, fertility requirement, fire tolerance, Flower color, flower conspicuous, foliage color, foliage porosity winter, foliage texture, frost free days min, fruit conspicuous, growth form, Growth rate, Hardiness zones, Lifecycle, lifespan, Light, Mature height, Minimum temperature, Native status, Nitrogen fixation, Nursery availability, precipitation max in, precipitation min in, propagation, resprout ability, root depth in, seed spread rate, Soil pH, Soil pH (upper), Tolerance of wet soil, Toxicity, Type, vegetative spread rate, Water need.
- Derived by a fixed rule from those columns: Guild layer.
Read our full data sources and methodology.
Find more plants for your zone with the Plant Finder.