Showy milkweed.

At a glance

Care level

Easy

Plant type

Perennial

Light

Full sun

Indoor light

Direct sun

Water

Every 7 to 14 days

Mature size

3 to 4 feet

Growth rate

Medium

Hardiness

USDA 3 to 9

Bloom time

Late spring to mid summer

Care

Plant this in a spot with plenty of sun and well draining soil. Watch for aphids on the stems, which are common but usually harmless. Allow the soil to dry out between waterings to keep the root system healthy.

Watering

Water deeply once established, but let the soil dry out between sessions.

Feeding

A light application of compost in the spring is plenty for this hardy plant.

Pruning

Cut the stems back to the ground in late autumn or early winter after the foliage dies.

Repotting

This plant prefers to stay in the ground, but if container grown, move to a larger pot every few years.

Soil

Well draining, sandy or loamy soil

Soil pH

6.0 to 7.5

Temperature

-30 to 35°C

Humidity

20 to 50%

Safety

People

All parts of the plant are toxic if eaten and the milky sap can cause skin irritation.

Pets

This plant contains cardiac glycosides and is toxic to cats and dogs if ingested.

Children

Keep children away from the plant to prevent accidental ingestion or sap contact with eyes or skin.

Contact allergens

The milky latex sap can cause contact dermatitis in sensitive individuals.

Airborne allergens

The pollen is not considered a significant airborne allergen.

Edibility

This plant is not for consumption as it contains cardiac glycosides that are toxic if ingested.

How to identify it

• Large, thick, oval shaped leaves
• Soft, velvety hairs on foliage
• Clusters of pink, star shaped flowers
• Large, warty seed pods

Height

0.6 to 1.2m

Spread

0.3 to 0.6m

Leaves

gray-green, deciduous

Flowers

pink, purple, 1 to 2cm

Fruit

green, brown, Late summer to fall

Problems to watch for

• Aphids · Small insects that cluster on new growth and flower buds, though they rarely kill the plant.
• Milkweed bugs · Orange and black insects that feed on the seeds and plant tissues.

Growing it

Propagation

seed, division

When to plant

spring, fall

Plant in large drifts to make it easier for pollinators to find your garden.

Grows well with

• Purple Coneflower · They share similar sun and water requirements while providing a nice color contrast.
• Little Bluestem · This grass provides a beautiful structural backdrop for the milkweed.

Similar species

• Common Milkweed · It is a close relative with a similar growth habit but slightly different flower shape.

Science

Family

Apocynaceae

Genus

Asclepias

Order

Gentianales

Class

Magnoliopsida

Native range

Western and central North America.

Conservation

It is not currently listed as endangered, though it is a vital native species that should be protected in its natural habitat.

It thrives in open, sunny areas and provides essential habitat for various insects.

Value to wildlife

larval host plant, nectar source

Pollinators

bees, butterflies, moths

Uses

pollinator garden, native plant restoration, meadow planting

Taxonomy resolved against GBIF.

Questions people ask

Does it need a lot of water?

No, it is quite drought tolerant once established.

Will it take over my garden?

It can spread by rhizomes, so give it space or use a barrier if you have a small garden.

Where the name comes from

The genus name Asclepias honors the Greek god of medicine, while the species name speciosa means showy or beautiful.

Good to know

• The flowers are arranged in large, fragrant, star-shaped clusters.
• It spreads via underground rhizomes to form colonies.
• The seed pods split open to release seeds attached to silky white hairs that travel on the wind.
• Native American tribes historically used the fibers for cordage and the roots for medicinal purposes.

Also in

• Plants toxic to cats and dogs