Cosmos sulphureus

Cosmos sulphureus is also known as Bidens sulphurea or Yellow Cosmos. It is part of the Asteraceae family of plants. It is a half-hardy annual. It is native to Mexico, Central America, and South America.

Most cultivars’ height range between 30cm to 90cm or 1 to 3ft. The foliage is opposite and pinnately divided. The flowers range from yellow to oranges and red. It flowers through summer and autumn.

Cosmos sulphureus
Yellow Cosmos sulphureus at Cleary Garden in London

How to grow Cosmos sulphureus:

Cosmos sulphureus, commonly known as Sulphur Cosmos, is a vibrant and easy-to-grow annual plant that adds a burst of color to gardens and landscapes. Here are some tips on how to grow and care for Cosmos sulphureus:

Sunlight: Cosmos sulphureus thrives in full sun. Ensure that it receives at least 6-8 hours of direct sunlight daily. This will promote healthy growth and abundant flowering.

Soil: Plant Cosmos sulphureus in moist, well-drained soil. While it can tolerate a range of soil types, it prefers slightly alkaline soil. Ensure that the soil is loose and fertile, as this will provide a favorable growing environment for the plant.

Watering: Cosmos sulphureus is a drought-tolerant plant once established. However, during its initial growth phase and on extremely hot days, regular watering is beneficial. Water the plant deeply, allowing the soil to dry out slightly between waterings. Avoid overwatering, as this can lead to root rot and other moisture-related problems.


Cosmos sulphureus is a relatively low-maintenance plant. It has good tolerance to pests and diseases, but occasional monitoring is recommended. Watch out for common garden pests such as aphids or spider mites, and take appropriate measures if infestations occur. Regularly inspect the plant for any signs of disease or nutrient deficiencies, and address them promptly.

Deadheading: Deadheading, or removing faded flowers, is a simple and effective technique to prolong the flowering season of Cosmos sulphureus. Regularly remove spent blooms to encourage the development of new buds and continuous flowering. Deadheading also helps maintain the plant’s overall appearance and prevents self-seeding, which can result in an overabundance of seedlings.

Cosmos sulphureus
Beautiful flowers of Cosmos sulphureus at Cleary Garden, London

Fertilization: Cosmos sulphureus generally doesn’t require heavy fertilization. However, incorporating compost or well-rotted organic matter into the soil before planting can provide a nutrient-rich foundation for the plant. If desired, you can apply a balanced, slow-release fertilizer during the growing season to support healthy growth and blooming.

Cosmos sulphureus
Bright orange flowers of Cosmos sulphureus at Cleary Garden London


Cosmos sulphureus can be easily propagated from seeds. Sow the seeds directly into the garden bed after the danger of frost has passed, or start them indoors a few weeks before the last expected frost date. Cover the seeds lightly with soil and keep them consistently moist until germination occurs. Once the seedlings are large enough to handle, thin them to the desired spacing to allow for proper airflow and growth.

By following these guidelines, you can successfully grow Cosmos sulphureus and enjoy its cheerful, colorful blooms throughout the growing season. Whether in garden beds, borders, or containers, this drought-tolerant plant adds a touch of vibrancy and charm to any landscape.

Cosmos sulphureus attracts birds and butterflies. It is self-seeding. It is considered invasive in the United States. Propagate Cosmos sulphureus from seeds. Usually, it germinates between 1 to 3 weeks depending on the climate. It flowers about two months after germination. It is generally disease-free and pest-free. Watch out for gray mold, slugs, and aphids.

Culinary Use:

They use Cosmos sulphureus in food in Indonesia it is called Lalab or Gudang. These are the young shoots of Cosmos sulphureus. They are consumed raw as well as cooked. In Thailand. they make tea from flowers. The flowers can be used as a dye for fabric or wool.

Cosmos sulphureus
Colorful flowers of Cosmos sulphureus at Cleary Garden, London

Cosmos sulphureus photos on this page are photographed at the Cleary Garden in London. Cleary Garden is a small stepped terrace garden that was created after the bombing of World War II.

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