Japanese Spiraea Dart’s Red A dwarf shrub with showy red flowers, Spiraea japonica Dart's Red is a small, deciduous shrub with a mound-forming, bushy habit, suitable for a smaller garden. The lance-shaped leaves are deep green and slightly toothed, and red-tinted when they first emerge. Attractive, small clusters of carmine-red flowers are borne in June, fading to rose-pink with age. Mulch with well-rotted manure, garden compost or leaf-mould to keep moisture in the soil. An easy plant, generally pest- and disease-free, and particularly good in borders. Japanese Spiraea Dart’s Red holds the RHS Award of Garden Merit. Site: Tolerates exposureSoil: Any moist but well-drained soilPosition: Full sun or partial shadeSeason of interest: Midsummer in particularHardiness: Fully hardyHeight: 2.5 to 3ft (75-100m) Spread: 2.5 to 3ft (75-100m) in 5-10 years