Butterfly Bush (Buddleja davidii)

plants, terrestrial, tier 5

Butterfly Bush, Orange-eye butterfly bush, summer lilac

Buddleja davidii

Family: Scrophulariaceae

History & Introduction

Butterfly bush is native to China. It was sought out as an ornamental plant due to its beautiful and copious flowers that attract butterflies and other pollinators. Since its introduction to North America in the early 1900s, it has escaped plantings in the Northeast, Southeast, mid-Atlantic and western US. It has been planted to attract pollinators. Although butterflies are attracted to the nectar, it is a low quality source of nectar. As well, this plant’s foliage does not support native caterpillars.

Identification

Habit: Deciduous shrub reaching 3 to 15 feet tall. Weeping branches can be pulled further down by the conical flowers.

Leaves: Lance shaped leaves are 6 to 10 inches in length. Leaves are opposite. Appears velvety.

Flowers: Arching stems end in tubular flowers. Each flower has four petals. Flowers can be purple, red, pink, white. Flowers produce nectar that butterflies find attractive.

Fruit: Pods are upright and small, and can be difficult to see in the flower. Produces thousands of seeds that are dust-like and distributed by the wind.

Phenology: Flowers bloom May to August.

Habitat

Prefers average soil that is well drained. Once established, it can survive in fairly dry habitats. Can be found escaping ornamental plantings along riparian areas, in roadside ditches, and coastal forest edges.

Dispersal

Seed can be spred via wind. Many different varieties are sold horticulturally.

Damage and Impact

Butterfly bush has the most ecological impact by displacing native plants when it escapes to natural areas. Once established in a natural area, butterfly bush can displace native plants. Native plants are important for pollinators because they provide them with a natural nectar source. Moreover, without host plants for the larval stage (caterpillars) of growth, pollinators will not be able to reproduce. Even if butterfly bush is planted in your garden, without host plants for caterpillars, the habitat will not be sustainable for the full life cycle of a pollinator. Removal of butterfly bush can be difficult as the plant can easily re-sprout from cutting or mowing. Seeds can also stay viable in the seed bank for several years.

Prevention

Do not plant butterfly bush. Wherever you see butterfly bush growing in natural areas, please document it in iMapInvasives or iNaturalist. If you have butterfly bush in your garden, consider hand pulling or removing flowers (deadheading/pruning) before they seed. Flowers can then be placed in the trash (do not compost).

Control

Chemical control:

For best results, use the ‘cut-stump’ method. Cut the stems/trunk at the base and apply concentrated glyphosate (such as in Roundup) or triclopyr (such as in Garlon or Brush BGon) to the freshly cut surface. It is best to treat butterfly bush in the late summer or early fall.
*When using herbicides, always read and follow label directions for rates, spraying conditions, and appropriate protective equipment, it’s the law. For more information regarding chemical control and potential permit requirements, please see our page on Managing an Invasion.

Manual control:

Hand pulling seedlings or digging out is recommended when the plant is young.

Native Alternatives:

Common milkweed ( Asclepias syriaca)
Butterfly weed (Asclepias tuberosa)
Sweet pepperbush ( Clethra alnifolia)

Want more information on emerging horticultural invaders? Watch theOrnamental Invasive Species Webinar recorded on March 24, 2022 with CCE Suffolk and LIISMA