Aster, Wood's Purple Overview Category: Perennials Common Name: Aster, Wood's Purple Botanical Name: Aster divaricatus 'Wood's Purple' Sun Exposure: Full sun Height: 12-15 in. Spread: 12-18 in. See notes | Back to perennials Notes Another winning cultivar, combining dwarf stature with mildew resistance. Dark purple flowers in August through October make this a great addition to the autumn perennial border. Full sun and well drained soils are best.