Spiraea japonica 39neon flash39 is a lovely mound45forming deciduous shrub with foliage that starts off rich45green before turning to dark burgundy in the autumn provide this japanese spirea with plenty of sun and you39ll enjoy bright neon45red flowers from may until october as popular with insects as humans 39neon flash39 is on the rhs perfect for pollinators list an excellent choice if you39re seeking to grow a low hedge or for a mass planting scheme height a