Most of these beautiful perennials are native to Eurasia, with only two from North America — the New York and New England asters. Their one-inch flowers are starbursts of closely packed, narrow petals in intense blue, purple, lilac, pink, or white. They brighten a garden in late summer through fall and are great for attracting butterflies, bees, and other pollinators. The word “aster” means star in Greek, and it sparkles as the September birthday flower and also for a 20th wedding anniversary.