Buddleja davidii 'Black Knight' (Butterfly Bush) is a vigorous large deciduous shrub with gracefully arching branches, studded with lance-shaped, dark green leaves with white-felted undersides, and sweetly scented, elongated panicles of dark purple, almost black flowers. Borne at the tips of current year's growth, the long flower spikes, up to 10 in. (25 cm), are on display from mid summer through early fall and sometimes to first frost. A superb, easily-grown plant that is favoured by butterflies and provides late summer to fall flowers when few other shrubs are in bloom. Excellent for cutting. Grows with an arching, spreading habit, up to 5-8 ft. tall (150-240 cm) and 4-6 ft. wide (120-180 cm). This shrub will naturalize by self seeding. A full sun lover, this plant is best grown in average, medium moisture, well-drained soils.