Buddleia davidii ‘Black Knight’

('Black Knight', Butterfly Bush)


Hardiness Zones:

 5a  5b  6a  6b  7a  7b  8a  8b  9a  9b

Quick Overview:

‘Black Knight’ is a butterfly bush cultivar which features almost black flowers. It is a deciduous shrub with an arching, spreading habit which typically grows 6-8′ tall if not cut back in late winter and 4-5′ tall if cut back. Features spike-like 4-10" long terminal clusters of very dark purple flowers which bloom from June to September and sometimes to first frost. Flowers are fragrant, and, as the common name suggests, very attractive to butterflies. Willowy gray-green foliage. Popular fresh cut flower.

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Easily grown in average, medium, well-drained soil in full sun. Becomes weedy and sparse with diminished flowering performance if not grown in full sun. Does poorly in wet conditions. In USDA Zones 5 and 6, this plant will often die to the ground in winter and therefore is often grown therein in the manner of an herbaceous perennial. Even if plants do not die to the ground in winter, they usually grow more vigorously, produce superior flowers and maintain a better shape if cut to the ground in late winter each year. Removal of spent flower spikes during the growing season will encourage additional bloom.

Additional information

Common Name

'Black Knight', Butterfly Bush

Botanical Name

Buddleia davidii 'Black Knight'


3 gallon

Evergreen or Deciduous


Hardiness Zone

5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b

Growth Rate


Light Requirements

Part-sun, Sun


6 to 8 ft.


6 to 8 ft.

Soil Condition


Water Needs


Blooming Period

early Summer through frost

Flower Color

dark purple



Foliage Color


Deer Resistant


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