Alternate-leaf Butterfly Bush

Buddleja davidii, Buddleja alternifolia

Cultivars: 'Unique', 'Argentea'

Alternate-leaf butterfly bush is a graceful, arching shrub that brings a soft, fountain-like silhouette to mixed borders. In late spring to early summer it blooms along the previous season’s stems, producing rows of small lavender flowers that look like garlands draped over the branches. The effect is airy and elegant rather than upright and spiky, and it plays well in naturalistic designs, pollinator beds, and shrub groupings where movement and form matter. Its bloom timing is also a plus, it provides early-season pollinator value before many summer shrubs hit their stride.

Plant Characteristics
Genus
Buddleja
Species
Buddleja davidii, Buddleja alternifolia
Cultivar
‘Unique’, ‘Argentea’
Family
Scrophulariaceae
Plant Characteristics
Foliage Interest
Pollinator-Friendly
Spring-Blooming
Plant Color
gray-green
Flower Color
Lavender
Bloom Time
Late Spring - Early Summer
Height
10'15'
Width
10-12'
Water Use
Low-medium
Care Instructions

Alternate-leaf butterfly bush prefers full sun and well-drained soil. It has low to medium water needs once established and generally performs best when not overwatered. The critical maintenance note is pruning timing: it blooms on old wood, so heavy pruning in fall or early spring will remove flower buds and reduce bloom the next season. Prune only after flowering, and keep it light, remove a few older stems to shape and renew, but avoid hard cutbacks unless you are willing to sacrifice flowers for a season. Fall dieback cutback is not applicable and not recommended. Winter protection is usually unnecessary in Rocky Mountain climates when sited in sun with drainage, but avoid exposed, icy wind tunnels if you can.