How to grow cosmoses

Cosmos is an annual flower gardeners tuck into beds and borders for a long bloom that keeps going from early summer into fall with little attention. The finely cut, lacy foliage takes up little visual space, so the plant reads as airy rather than crowding out neighboring crops, and the daisy-like flowers in white, pink, and maroon draw bees and butterflies through a garden. It self-sows readily where happy, so a stand planted once can return the next year on its own. It tolerates lean soil and needs little water once established, fitting well at the edge of a garden where fertilizer goes to the food crops instead.

The hardest part of growing cosmos well is resisting the urge to fertilize it. Utah State University Extension warns that nutrient-rich soil produces plants that are weak-stemmed and floppy, bloom late, and flower sparsely. A second-year gardener who has learned to feed everything else in the garden generously often extends that habit to the cosmos alongside it, or plants it in soil already built up for heavy feeders. The result is a leggy plant that falls over in the first summer storm and needs staking, producing far fewer blooms than it would in poor, unimproved soil.