"Redbuds say spring," says Andrew Bell, curator of woody plants at the Chicago Botanic Garden. When their glowing magenta flowers appear, outlining the branches, a garden seems to pulse with color. Redbud flowers last up to 3 weeks before the big, heart-shaped leaves emerge. Redbuds are native North American trees suitable for natural landscapes, but they are also striking in formal settings, as specimens, and in groves. Redbuds grow to about 25 feet tall, although they tend to stoop as they age. The seedpods are attractive, but seedlings can be hard to pull if you don't catch them when they're small. Fall foliage is bright yellow. Hardy in Zones 4 to 9.