Cosmos Sulphureus Yellow Cosmea Flower Plant
YELLOW COSMEA
Yellow cosmeas originally came from slightly more southern regions of Latin America, not only from Mexico, where Cosmos bipinnatus grows naturally, but also from the warmer regions of Central America and the north of South America. It is consequently even more sensitive to cold and suffers more from cool, wet summers. Its cultivation is otherwise the same as that of the ordinary cosmea, certainly now that recent decades have seen the development of lovely cultivars which are better at withstanding cooler climates. It is best to sow the seed indoors in March-April and not to put the plants out-of-doors in pots, containers, or directly in the ground until the end of May. They will then begin to flower by mid-July, but if you sow out-of-doors in May, the flowers will not appear until August.
The cultivars often grow up to 39 in tall, but dwarf varieties which grow no taller than about 10 in are also available. Cosmos sulphureus ‘Bilbo’ is one of those small ones and bears semi-double orange flowers. It is on sale as a flowering plant as early as mid-May.
The name “yellow cosmea” is misleading because most of the cultivars bear orange to reddish-orange flowers. They are about l’/2 in wide. They naturally have about eight or nine petals, but there are also many semi-double cultivars on the market; Cosmos sulphureus ‘Klondyke Sunny Red’ is a good example. The variations in the color of yellow cosmeas shows up clearly: it varies from yellowish to reddish orange. The flowers of Cosmos sulphureus ‘Diablo’ are deep, flaming red. Still, there are also truly “yellow” cosmeas. Cosmos sulphureus ‘Crest Lemon’ is a real beauty because of the magnificent lemon-yellow shade of the single flowers towering above the foliage. The plant does not grow more than 20 in tall; in spite of this, it provides magnificent cut flowers for vases. Unfortunately, ‘Crest Lemon’ is available only in small quantities.
Cosmos sulphureus is also known as Sulfur Cosmos and Yellow Cosmos. Its native habitat is Central America.
This species of Cosmos is considered a half-hardy annual, although plants may re-appear via self-sowing for several years. Its foliage is opposite and pinnately divided. The plant height varies from one to seven feet. The original and its cultivars appear in shades of yellow, orange, and red. It is especially popular in Korea and Japan, where it is often seen in mass plantings along roadsides.