Butterfly weed

Sun

Full sun, with at least 6 hours of direct sunlight daily.

Water

Water regularly during the first growing season, letting the soil dry slightly between waterings. Established plants usually need watering only during prolonged drought.

Soil

Well-drained sandy, gravelly or loamy soil; tolerates poor soil and a range of pH levels. Avoid waterlogged ground, especially in winter.

Height

1-3 ft (0.3-0.9 m)

Spread

1-2 ft (0.3-0.6 m)

Flowers

Early to late summer, depending on climate; usually bright orange, occasionally yellow.

Foliage

Narrow, green leaves arranged mostly alternately on upright, hairy stems. Dies back for winter and emerges late in spring.

Growth

Moderate once established; seedlings may take two or three years to flower well.

Care needed

Low

• Plant in a permanent sunny position; avoid disturbing the deep taproot.
• Water new plants deeply during dry spells, but do not keep the soil constantly wet.
• Skip routine feeding; rich soil and excess nitrogen can produce weak, floppy growth.
• Keep mulch clear of the crown; use a thin gravel mulch where winter wet is a problem.
• Avoid dividing established clumps; raise replacements from seed instead.

Pruning. Remove spent flower clusters if you want to limit self-seeding, checking first for caterpillars. Leave stems standing over winter, then cut them to just above ground level in early spring before new shoots appear.

Late winter

Give seed about 30-60 days of moist chilling in the refrigerator before spring sowing.

Early spring

Cut back old stems and mark the crown so you do not disturb its late-emerging shoots.

Late spring

Plant young plants after severe frosts have passed; water them in thoroughly.

Summer

Water young plants during dry spells and inspect shoots for aphids and monarch caterpillars.

Late summer

Remove developing seed pods to limit seedlings, or leave a few to mature for seed collection.

Autumn

Sow fresh seed outdoors for natural winter chilling and check that rain drains freely around established crowns.

• Plant in small groups near the front or middle of a sunny border for concentrated orange summer colour.
• Combine with little bluestem and purple coneflower in a prairie-style planting with contrasting flowers and fine grass foliage.
• Use in gravel gardens and dry, open beds where richer-soil perennials need too much watering.
• Include in North American native pollinator gardens as both a nectar source and a monarch caterpillar host.

Garden styles it suits: Native meadow, Midwest prairie, Pollinator garden, Wildlife garden, Dry gravel garden and New perennial (prairie).

Plant it with: Purple coneflower, Little bluestem, Prairie dropseed, Lanceleaf coreopsis, Black-eyed Susan and Blazing star.

Wildlife: Flowers provide nectar for butterflies, native bees and other insects. In North America, the leaves feed monarch caterpillars, although females may favour other milkweed species. Caterpillar feeding is normal; avoid insecticides on occupied plants.

• Crown or root rot in wet soil: improve drainage or replant in a raised, freely draining position; avoid heavy winter mulch.
• Yellow oleander aphids on stems and buds: tolerate small colonies or remove by hand, checking carefully for monarch eggs and caterpillars first.
• Poor establishment after moving: transplant only very young plants and keep the root system intact; replace badly damaged mature plants with seedlings.
• Weak growth or few flowers in shade: move young plants to full sun and avoid nitrogen-rich fertiliser.

Treat all parts, including roots, leaves and stems, as toxic to people, cats, dogs and horses if eaten. Poisoning can cause digestive upset and potentially affect the heart; large amounts may be serious. Do not use the roots as a home remedy, and seek medical or veterinary advice after ingestion.

• Tropical milkweed (Asclepias curassavica)

  Usually has red-and-yellow flowers, smoother stems and opposite leaves. Butterfly weed has hairy stems, mostly alternate leaves and usually uniformly orange flowers.

• Swamp milkweed (Asclepias incarnata)

  Usually taller, with opposite leaves and pink or white flower clusters. It prefers moist soil, unlike the dry, freely draining conditions suited to butterfly weed.

Asclepias honours Asclepius, the Greek god of medicine, while tuberosa refers to the thickened root and butterfly weed describes the insects attracted to its flowers.

Propagation. Grow from seed sown outdoors in autumn, or sow in spring after about 30-60 days of moist chilling. Use deep pots and plant out while young to minimise taproot disturbance. Seed-grown plants vary in flower colour and may take two or three years to bloom.

Accepted botanical name

Asclepias tuberosa

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois and Indiana.

Measured

Soil pH 4.8 to 6.8. Average height 56 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.