How To Grow Butterfly Weed (Asclepias tuberosa)

by Matt Gibson

If you would like to attract a continuous visitation from various butterflies and hummingbirds to your garden (who wouldn’t?), consider adding butterfly weed to your flower garden beds this season. The one and a half to two and a half foot-tall perennial thrives in dry, sunny sites all across USDA hardiness zones three through nine. When mature, the butterfly weed boasts two to five inch clusters of yellow-orange to bright orange flowers.

The butterfly weed gets its name from providing the main food source for butterflies, specifically monarch’s, who use the butterfly weed as a host plant during their caterpillar and butterfly stages. The monarch, however, is not the only pollinator that is attracted to butterfly weed. Butterflies of all kinds, as well as honey bees, bumble bees, and hummingbirds, are all frequent visitors of the butterfly weed. Butterfly weed also attracts swallowtails, painted ladies, hairstreaks, and fritillaries. Unfortunately, patience is needed to enjoy what the butterfly weed can bring to your garden, as plants typically don’t flower until their third year. The wait may be long, but butterfly weed blooms do not disappoint. With a splendid array of bright orange flowers and a long list of frequent visitors, it is a good idea to have your camera ready. 

An herbaceous member of the dogbane family, butterfly weed is native to the dry fields, prairies, meadows, woodlands, canyons, and hillsides of the eastern United States and Canada. It grows naturally in loamy or sandy well-drained soils in full sun locations. Butterfly weed is cultivated for its ornamental value and its flowers are used for the preparation of various cut flower bouquets.

Each butterfly weed plant develops an erect, multi-branched stem that grows around one to three feet high. Each branch is covered in hairs and becomes woody after a few years, developing flower clusters at the ends of each branch once the plant reaches maturity. Alternately arranged on the stem, butterfly weed leaves are lanceolate, linear, or oblong, with smooth edges and pointed tips. The upper side of the leaves are both darker and shinier than the under side. 

Three years after planting, butterfly weed begins to produce bright orange flower clusters of small, five-petaled, star-shaped flowers. Blooming from May to September, butterfly weed packs a pollinator party throughout the growing season.

The fruit of the butterfly weed plant is a narrow greyish-green pod covered with hairs, which ripens at the end of summer or the beginning of fall. Each pod contains hundreds of seeds. The seeds are equipped with silky, white tufts of hair which help the seeds take flight on the wind to disperse and find new homes.

People and Pets Shouldn’t Eat It

All parts of the butterfly weed are toxic to both humans and animals. The flowers, stems, leaves, and root will all cause diarrhea and vomiting if ingested. Touching the sap could cause skin irritation. Eating just a small amount of butterfly weed can get you sick. This is even more of a danger with small animals, as tiny doses, as low as .01 to .05 percent of their body weight, could kill them. This is generally more of an issue with grazing animals than with pets, but exercise extreme caution with plant placement and seek immediate medical attention if you suspect that a child or pet has eaten butterfly weed. 

Varieties of Butterfly Weed

True orange is the typical flower color of the original hardy, species version that is often sold as Asclepias tuberosa. “Hollow Yellow” is a yellow flowered variety. “Cinderella” is a cultivar with pinkish-red colored flowers. “Gay Butterflies Mix” is a family of species, with plants in colors of red, orange and yellow.

The “Silky Mix,” or Asclepias curassavica, has several beautiful variations of the original A. tuberosa. Silky Deep Red Butterfly Weed bears flowers with yellow-orange crowns and deep red-orange corellas for a lovely two-toned bloom. Silky Scarlet is a tropical species that is a perennial in frost-free regions and an annual in regions that experience freezing temperatures. The Silky Scarlet produces blooms that range in color from salmon and bright pink, to shades of yellow, orange, and red. Silky Gold produces golden yellow flowers that bloom all year long in frost-free areas.

Growing Conditions for Butterfly Weed

Butterfly weed performs best in full sun locations but can adapt to some shade, as long as it receives at least six hours of direct sunlight per day. Butterfly weed is adapted to less-than-ideal soil conditions, and is well-suited to clay, dry, and even rocky soil and drought conditions. Hardy to USDA zones three through nine.

Care of Butterfly Weed

Keep butterfly weed well watered during its first season but don’t worry about watering it once it is established. No fertilization is needed for butterfly weed. Just a topdressing of compost or composted manure added once per year is all that is needed to provide nutrients for butterfly weed to thrive.

How to Plant Butterfly Weed

Sow butterfly weed seeds directly into the soil in the fall for spring sprouts, or sow indoors during the winter after cold stratification. Because of their long taproots, direct sowing is the preferred method of propagation.

How To Propagate Butterfly Weed

Butterfly weed can be propagated by seed or by root cuttings. Because butterfly weed has a long taproot, which can be very difficult to transplant, propagation by seed is highly recommended. Seeds can be harvested and saved around the beginning of fall. They can be brought indoors or can be buried in the ground just under the topsoil, to survive the winter, then planted directly into your garden beds in the early spring.

Companion Planting With Butterfly Weed

The following plants will all grow well with butterfly weed:

• Coreopsis
• Russian Sage
• Coneflower
• Catmint
• Rudbeckia
• Ornamental Grasses such as fountain grass, northern sea oats, or switchgrass

Garden Pests and Diseases of Butterfly Weed

If you grow your butterfly weed in a very wet location, crown and root rot can be an issue. Reduce the risk of crown rot by planting your butterfly weed in a hole with the crown set just slightly above the soil line. Reduce the risk of root rot by increasing soil drainage and by taking care not to overwater your butterfly weed plants.

Yellow-orange oleander aphids (Aphis nerii), or milkweed aphids, form colonies which envelop the plant’s stems and leaves as the pests feed on the sap. The pests excrete honeydew in massive amounts, a clear, gooey waste substance that attracts a black, sooty mold. The mold covers the plant in layers of powdery, soot-like fungal strands. Small infestations of oleander aphids can be treated by knocking them off with a burst of water from the watering hose. Heavier infestations may need multiple treatments of insecticidal soap or horticultural oils, sprayed to saturate stems and leaves.

Common Questions and Answers About Butterfly Weed

Do you fertilize butterfly weed?

Feed with compost in the fall, then top with a layer of mulch. In spring, feed with a diluted dose of slow release fertilizer blend.

Does butterfly weed come back every year?

Yes, in zones where butterfly weed dies back in winter, it sprouts again in spring as a perennial.

Do you cut back butterfly weed in the fall?

Start with clean, sterilized gardening shears, and disinfect the tool when moving between plants. Wear gloves to protect yourself from the skin irritation butterfly weed can cause. Prune your butterfly weed between late winter and early spring before new growth sprouts. Cut the plant back to a third or half of its starting height. Make all your cuts no more than a quarter inch from a leaf or leaf node.

How do you propagate butterfly weed?

You can propagate butterfly weed from seed, via cuttings rooted in water, or by division or separation.

How often should I water butterfly weed?

Water young plants whenever the soil dries out to keep it moist until they’re well established and showing new growth. Once well established, butterfly weed should only need water during periods of extreme drought.

How tall does butterfly weed grow?

Butterfly weed grows to between one and a half and three feet tall when mature.

Is butterfly weed a perennial?

Butterfly weed is a perennial, which means they go dormant each winter and bounce back in the spring.

Is butterfly weed invasive?

Unlike common milkweed (Asclepias syriaca), butterfly weed (Asclepias tuberosa) does not have the quickly spreading roots that qualify it as invasive.

Is butterfly weed poisonous to humans, dogs, or cats?

Butterfly weed is toxic to both humans and pets. In humans, it requires large doses to cause discomfort, but because children, dogs, and cats are smaller, their risk is more substantial. Consumption of butterfly weed can cause bloating, fever, difficulty breathing, dilated pupils, muscle spasms, or death. For ingestion by humans, call the Poison Control Center at 800-222-1222, or for ingestion by animals, call ASPCA’s Animal Poison Control Hotline at 888-426-4435.

Want to learn more about growing Butterfly Weed?

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Cornell University covers Butterfly Weed

Gardening with Charlie Nardozzi covers How to Grow Butterfly Weed

GreenHouse Product News covers Asclepias tuberosa Butterfly Weed

SFGate Homeguides covers Cutting Back Butterfly Milkweed

SFGate Homeguides covers Butterfly Weed Plant

Horticulture Magazine covers Perennial Plant of the Year: Asclepias tuberosa

Hunker covers How to Take Care of Milkweed

Hunker covers Butterfly Plant Poisonous

Live Monarch covers Growing Instructions for Milkweed

University of Minnesota covers Finding, Collecting and Growing Milkweed

Monarch Watch covers Milkweed

Stewardship Garden covers Growing Milkweed for Monarchs

Plant Care Today covers Butterfly Weed Care

SoftSchools.com covers Butterfly Weed Facts

the Spruce covers Growing Butterfly Weed in the Garden

University of Wisconsin-Madison covers Butterflyweed