Shrub
Butterfly bush
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Flowers | Flowers in July | Flowers in August | Flowers in September | |||||||||
| Plant | Plant in March | Plant in April | Plant in May | Plant in September | Plant in October | |||||||
| Prune | Prune in March | |||||||||||
| Looks good | Looks good in July | Looks good in August | Looks good in September |
Overview
Few shrubs pull in butterflies like buddleja, whose honey-scented cones open in high summer just as peacocks, red admirals and commas are on the wing. The species can reach three metres in a season, but compact varieties such as the Buzz and Lo & Behold series stay around a metre, making them fine for pots and small gardens. 'Black Knight' has deep violet flowers and 'White Profusion' is a clean white.
Where to grow butterfly bush
Full sun and sharp drainage are all it really asks for. It copes with chalk, rubble and windy sites, which is why it turns up on railway banks. Plant it where you can watch the butterflies, perhaps alongside Verbena bonariensis and sedum for a long nectar season.
Planting
Plant container-grown shrubs in spring or early autumn. Little soil improvement is needed; in fact, rich soil makes floppy growth. Water regularly through the first summer, after which established plants rarely need it.
Care through the year
Spring
Prune hard in March, then scatter a little general fertiliser on very poor soil.
Summer
Snip off faded flower spikes every week or two; side shoots then produce smaller follow-on flowers.
Autumn
Shorten very long stems by about a third to stop wind rocking the plant loose.
Winter
Leave it be; the bare stems shelter overwintering insects until the spring cut.
Pruning
Buddleja flowers on new growth, so cut all of last year's stems back to a low framework about 30–60 cm high in March, just above a pair of fresh buds. Remove one or two of the oldest framework branches every few years. Compact varieties need only a lighter trim.
Propagation
Softwood cuttings in early summer or hardwood cuttings in autumn root without fuss. Named varieties will not come true from seed, and the seedlings are best pulled up anyway.
Common problems
It is generally trouble-free. The main issue is its habit of self-seeding into paving, chimneys and wild ground, which deadheading largely prevents. Capsid bugs and caterpillars may hole the leaves, but plants shrug this off. On cold, wet clay young plants can rot, so add grit.
Something else wrong? Diagnose it by symptom.
Month-by-month reminders
Jobs for this plant come round in March, April, May, September and October. Each month page lists everything else worth doing in the garden at the same time.
Related plants
Sources
Botanical names follow Kew's Plants of the World Online; growing attributes were checked against the references below. Text is our own. See our editorial policy.