How to prune clethra alnifolia 'ruby spice'

Late winter to early spring before new growth begins. Cut dead or crossing stems to the base. Each late winter, remove up to one-third of the oldest canes at ground level to encourage strong new basal growth. Very overgrown plants can be cut to 6–12 inches for full rejuvenation.

Annually for light tidying; hard rejuvenation every 5–7 years if needed. Clethra alnifolia 'Ruby Spice' benefits from the same approach as the species: remove dead stems and thin the oldest canes at ground level in late winter to promote vigorous flowering shoots. This cultivar is moderately vigorous and responds well to periodic hard renewal if it becomes too dense or leggy.

Cut dead or crossing stems to the base. Each late winter, remove up to one-third of the oldest canes at ground level to encourage strong new basal growth. Very overgrown plants can be cut to 6–12 inches for full rejuvenation.