Buddleja davidii is a favourite, fast-growing shrub from China. They not only make beautiful shrubs, but they also attract large quantities of butterflies to their nectar-rich flowers, which is how they derive their common name.

The fragrant flowers are borne in long spires in the late summer and early autumn, after most other shrubs have finished flowering. The most typical colour of the flowers is lilac, but there are lots of shades, varying from white to pink to deep purple. The flowers can look a little unsightly once they begin to fade and turn brown.

Buddleja are best planted out in spring, although container-grown plants can be planted out at any time, as long as the weather is not too hot or too dry. They are relatively hardy plants and will withstand most winters, although an occasional harsh one may cut them back.

Butterfly bushes must be pruned regularly, otherwise the flowers will decrease in size and the plant will tire and die. Each spring, cut back the previous year’s growth to within 3 to 4in (7.5 to 10cm) of where it started. This may seem rather drastic, but the bush will soon recover and start sprouting new growth.

Growing Requirements

Soil
The butterfly bush is an undemanding plant and will grow on a wide range of soils, including quite dry ones, as long as it is planted in a sunny position, though a little light shade will be tolerated.

Size
Buddleja will grow to a height of 13ft (4m) and spread to a similar size.

Propagation
Buddleja will self-seed and the resulting seedlings can be transplanted and used as new plants. To propagate favourite colour forms, it is essential to take cuttings from existing plants. These are best taken as hard wood cuttings in the early winter months but summer cuttings from soft, new growth can also be used.

Family: Scrophulariaceae
Genus: Buddleja