Cosmos Flower Reproduction. Jan 11 2017 Add compost yet hold back on fertilizers that contain high nitrogen which can encourage foliage to develop more rapidly than flower blooms. Plant phlox in the springafter the threat of frost has passedand space the plants 1 to 2 feet apart.
Annual comos are easily grown from seed. Plants that have male and female flowers growing on separate plants must rely on wind or pollinators such as bees and butterflies for reproduction. Jan 11 2017 Add compost yet hold back on fertilizers that contain high nitrogen which can encourage foliage to develop more rapidly than flower blooms.
Loosen the soil to about 12 to 15 inches deep then mix in a 2- to 4-inch layer of compost.
If the seeds of Cosmos flowers fall on bare ground the flowers can re-grow in spring. Keep an eye out for aphids slugs gray moulds. The annuals are particularly effective when massed and provide flowers for cutting over a period of months. Both the Cosmos sulphureus and Cosmos bipinnatus species of cosmos flowers are considered annual plants.