Cosmos are branching annuals with ferny foliage and pink, crimson, or white flowers that work well in the back of a border. Although introduced in 1799, cosmos did not beome popular for the garden or as the subject of breeding efforts until the early 1900s. The rest is now history. The variety 'Sensation' won the All-American Selection Award of Merit in 1936 for its clear colors of pink and white, on early-blooming, 3- to 4-foot-tall plants. 'Purity' is the glistening white form of cosmos in the 'Sensation' series. 'Sea Shells' has quilled florets. The Sonata Series cultivars are dwarf plants only growing to about a foot or two tall.
Noteworthy CharacteristicsOld-fashioned, reliable annual with pretty flowers and ferny foliage. Easy from seed.
CareFull sun and moderately fertile, moist but well-drained soil. Deadhead, but leave a few flowerheads to self-seed if desired. May need staking.
PropagationSow seed at 61°F in mid-spring, or sow in situ in late spring.
ProblemsStem canker, powdery mildew, Rhizoctonia stem rot, and sometimes gray mold, can cause problems. Aphids also occur.
- Genus : Cosmos
- Plant Width : 1 to 3 feet
- Plant Height : 3 to 6 feet
- Plant Type : Annuals
- Moisture : Dry to Medium
- Bloom Time : Early Fall, Early Summer, Fall, Late Summer, Summer
- Light : Full Sun
- Flower Color : Green, Pink, White
- Growth Rate : Moderate
- Maintenance : Moderate
- Characteristics : Self Seeds, Showy Foliage
- Plant Seasonal Interest : Summer Interest