Divide plants every 2 to 3 years in the spring or fall. Plants are longer-lived and spread more aggressively than other coreopsis.

The plant can be aggressive; if you wish to keep it in check, you'll have to contain the spread of the rhizomes either by cutting them or by blocking their progress with bamboo barriers or the like. Cultivars such as Eupatorium maculatum 'Gateway' are better-behaved. Pinch back in late spring to keep the plant more compact. If you're happy with this aggressive plant and wish to increase your supply of it and grow it in an additional spot in the landscape, undertake springtime division.