Growing Helianthus angustifolia Swamp Sunflower
Brighten your late summer garden with the swamp sunflower. This North American native perennial grows up to 8 feet tall. Use it as a back-of-the-border plant for natural, pollinator and perennial gardens. It tolerates moist soils as the common name implies, making it suitable for plantings along streams and ponds.
The two-inch diameter yellow daisy-like flowers appear late summer into fall. You’ll enjoy the late season color and all the native bees, butterflies and songbirds that stop by for a visit.
This is one of the showiest and best behaved of the native perennial sunflowers, but it does spread fairly quickly, reseeds, and has a tendency to flop when in full bloom.
Prune it back in June to encourage more compact, branched growth. Or select one of the more compact varieties like First Light at 3-4’ and Low Down at 2-3’ tall.
A bit more information: Grow swamp sunflower in an area where it has room to spread and remove the faded flowers to minimize reseeding and control its spread. Combine it with equally assertive flowers like little bluestem, wild bergamot and New England aster to minimize your need to intercede.