When the pods open in September and October seeds are readily carried by the wind. Seeds float, so runoff and irrigation water spread the seed. The seed can survive three years of burial in the soil. New plants readily become established from seed in areas free of other plant competition. 1 Green milkweed is perennial from a vertical rootstock.
Stems are mostly solitary or in pairs, and are up to two feet tall.
Leaves are usually opposite, up to four inches long, and extremely variable in shape. Plants from dry sites tend to have long narrow leaves, whereas those from moist sites are nearly round. About 20-80 pale green flowers occur in clusters. These are about two inches in diameter and are found in the upper leaf axils. Look for green milkweed on dry hills or slopes in sandy or rocky native prairie or dry upland woods.