Common milkweed is a native North American perennial and the primary larval host plant for the monarch butterfly in the eastern United States. It produces dense, fragrant pink-purple flower clusters in midsummer that draw monarchs, swallowtails, native bees, and milkweed beetles. Large, warty seed pods form in late summer and split in fall, releasing wind-dispersed seeds attached to silky white floss. It is one of the highest-value native plants a gardener can add to a sunny site.
The plant spreads by both rhizomes and seed and can form dense colonies over several years. Place it in a naturalized area or contained bed where spreading is acceptable. It emerges late in spring — mark crowns in fall to prevent accidental damage during early cultivation. Stems contain a milky latex toxic to most mammals but essential to monarch caterpillars, which sequester the plant's cardiac glycosides for their own chemical defense. Cold stratification for 30 days improves germination; fall direct sowing achieves this naturally.
Native peoples including the Ojibwe used cooked young shoots, flower buds, and unripe pods as food; raw plant material contains cardiac glycosides and must be thoroughly cooked before eating. Stem fibers were processed for cordage. During World War II, the buoyant seed floss was harvested as a kapok substitute for filling military life preservers. Latex was applied topically to warts in traditional practice, and root preparations were used as expectorants and diuretics.
Rust
Orange to brown raised pustules on the undersides of leaves, with yellow spotting on the upper surface. Heavy infections cause leaves to yellow and drop.
Remove and destroy infected leaves. Avoid overhead watering and improve air circulation. Apply a sulfur or copper-based fungicide if it spreads. Clear plant debris in fall.
Powdery mildew
White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.
Aster Yellows
Deformed, greenish flowers, stunted growth, and yellowed foliage. Flower centers may produce tufts of leafy growth instead of normal petals.
No cure. Remove and destroy infected plants immediately to stop spread. Control leafhoppers, which transmit the disease, and remove nearby weed hosts.
Aphids
Aphididae →Clusters of small soft insects on new growth and flower buds.
Knock off with a strong jet of water. Ladybirds and lacewings are natural predators. Insecticidal soap as last resort.
Milkweed Tussock Moth
Euchaetes egle →Dense clusters of tufted caterpillars with black, white, and orange hairs feed gregariously on leaf tissue, skeletonizing leaves from the margins inward. Heavy infestations can strip multiple stems bare by late summer.
Handpick early-instar clusters before they disperse across the planting. Plants reliably rebound from defoliation and larvae do not threaten root survival. Avoid Bt sprays and other insecticides — they are non-selective and will kill monarch caterpillars feeding on the same plants.