(Summersweet) Vanilla Spice™ Clethra has attractive glossy, dark green leaves. Its extra large pure white flowers are very fragrant and act as a magnet for Butterflies. Each flower is roughly the size of a dime and about twice the size of any other Clethra. Vanilla Spice™ offers a wonderful fragrance during the late summer months. A Proven Winners® ColorChoice® Flowering Shrub.