Rudbeckia lacinata 'Autumn Sun' (cutleaf coneflower) is a bold, late-season perennial for the back of the border. You get tall stems topped with coneflower-like, butter-yellow rays around a distinctive green cone, bringing strong color and structure from late summer into fall. Use it where you want height, movement, and plenty of pollinator activity.
Plant it in full sun for the strongest stems, but it also performs well in part shade, especially where the soil stays evenly moist. Mature clumps typically reach 60-84 inches tall and spread to fill a generous space, making it a natural choice for cottage gardens, meadow-style plantings, rain-garden edges, and mixed borders.
To keep plants looking their best, water during dry spells the first season and then as needed during extended heat. Cut stems back after flowering for a tidier look, or leave some seed heads to add texture into fall. Divide crowded clumps in spring if you want to refresh growth or share plants. In windy or very rich sites, give it room and consider a discreet support to help prevent flopping.
Pair 'Autumn Sun' with ornamental grasses, tall asters, Joe-Pye weed, or other sturdy late-blooming perennials. The bright flowers and strong vertical form make a reliable backdrop that carries your garden through the end of the season.