Buddleja davidii is a deciduous shrub that is 3-15 ft. (1-5 m) tall with arching stems.
Foliage
The leaves are opposite, 6-10 in. (15-25 cm) long, velvety and lanced-shaped.
Flowers
Flowering occurs from May to August, when dense clusters of tubular flowers develop. These flowers have 4 petals and can be purple, white or pink. The flowers produce high quantities of nectar and are attractive to butterflies, hence the common name.
Fruit
The developing pods are small upright ovate pods, which may not be readily visible through the remnants of the flower. When mature, the pods area a dark brown and opened at the tip. The seeds are dust-like particles which can easily be distributed by the wind.
Ecological Threat
Buddleja davidii readily invades disturbed sites and riparian areas. Although butterflies will use this plant as a nectar source their larvae cannot survive on it. By replacing native larval food source plants butterflybush can have a negative impact on wildlife.