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Buddleja davidii Black Knight


Butterfly bush

Beautiful fragrant flowers

This well-known and popular variety of the common buddleja is a vigorous shrub with arching branches growing to 1.8m (6ft). The large flower clusters appear in late summer, deepest violet, each flower with a tiny deep orange eye. The fragrance is strong and sweet and the blooms are very attractive to bees and butterflies, hence the common name (Butterfly Bush). A lovely choice for naturalistic schemes.


Plant in full sun. Ideal for dry gardens and coastal conditions. Perfect at the back of a border to rise above other shrubs, roses and perennials.


Any well-drained soil. Thrives on poor soil and chalk. Prune hard in late winter cutting back to 90cm (3ft) or less. Deadheading as the flowers fade prolongs the flowering season. 

Originally from China and Japan, Buddleja davidii is naturalised in many parts of the world

Plant details

In depth plant information

Property Value
Plant type Ornamental shrub
Flower colour
Foliage colour
Typically available April - September
Season of interest Autumn, Spring
Flowering July - October
Evergreen No
Plant height 250 cm - 400 cm
Plant width 250 cm - 400 cm
Fragrant flowers Yes
Attracts bees Yes
Attracts butterflies Yes
Plant height in 5 years 400 cm
Medicinal No
Hardiness zone (?) H5

Will perform best in these conditions

Property Value
Soil type Chalk, Clay, Sand, Loam
Light exposure Full sun, Part shade
Soil drainage Well drained, Moist
Planting instructions

Water the plant in its pot thoroughly before planting – give it a good soaking. Prepare the area by digging a hole twice the size of the pot. Dig compost into the base of the hole. Remove the pot and position the plant in the hole, with the top of the rootball about level with the surrounding soil. Refill the planting hole with a mixture of garden soil and compost, firming as you go. Water in well and keep well watered during the plant's first year.

Planting site Cottage garden, Informal garden, Coastal or drought resistant, Wildlife garden

Typically available

From April to September