Cosmos sulphureus is also known as sulfur cosmos and yellow cosmos. It is native to Mexico, Central America, and northern South America, and naturalized in other parts of North and South America as well as in Europe, Asia, and Australia.
Plant Cosmos sulphureus flowers, better known as golden cosmos, in your garden's sunniest spots for a spring-to-fall stream of nectar-feasting butterflies. This Mexican-desert native stands as high as 7 feet in its natural habitat. It now grows as an annual across the United States. Its yellow-eyed, golden- or clear-yellow cupped daisies crown branching stems of green, fernlike leaves. Hybridization of the plant has produced several smaller - but equally heat-tolerant - cultivars. They bloom in an array of yellows, oranges and reds for a festive display. Even first-time gardeners can successfully grow golden cosmos from seed.
Water regularly until plants are established or if it is unusually dry. Make sure you don't over-water cosmos; over-watering and over-fertilization can lead to plants with fewer flowers. Cosmos can tolerate dry soil, even in a hot, arid, sunbaked spot.
Medium light/Partly shaded – This is where the plant gets some morning sun or some afternoon sun. Morning sun is less intense than afternoon sun, so putting your plants a few meters in from an East facing window works for maximum sun while reducing the risk of burning.
The ideal blend of soil for plant growth is called loam. Often referred to as topsoil or black dirt by landscape companies, loam is a mixture of sand, clay, and silt.
Liquid fertilizers are applied more frequently, bi-weekly or monthly, for example. Granular products are used less frequently, perhaps once every month or two. Slow-release houseplant fertilizers break down slowly and release their nutrients in small amounts, over a longer period of time. A single application of most of these products lasts for three to four months.
Clip or pinch off dead leaves and stems. If stems have rotted at the root, pull them out, and make sure to let the soil dry out before the plant's next watering.
Hot weather is ideal for cosmos. They are not frost hardy. Plant your golden cosmos seed from early spring to summer, after the soil temperature has reached 65°F or higher.
Choose a wind-protected site for tall, golden cosmos plants varieties. Their mature, hollow stems are susceptible to breakage in heavy winds.
