If you don’t know them by name, they are the towering masses of bright, yellow, flowering plants that could cause whiplash the first time you see them.
Just when summer flowers are puttering out, the swamp sunflower comes into its own in late September and into October. They will bloom until the first cold snap.
According to the Georgia Wildlife Federation, the swamp sunflower loves moist soil but it is drought tolerant. It’s slow to emerge in the spring and takes a while to get growing, but once it does, expect plants 6 to 10 feet tall. Plant in full sun.
To keep the plants more compact and bushy, you can cut them back by a third in June, according to an article on the HGTV Web site.
They can be overly aggressive, but that makes for easy sharing. Divide the root mass in spring or fall.