Cosmos caudatus – Urban Biodiversity Initiative (UBI)

Common name: Cosmos, wild cosmos

Local name: Ulam raja

Scientific name: Cosmos caudatus

Distribution: Pantropical

Conservation Status: Least concern, Cultivated, Naturalised species

Description

The name of the plant means ‘king of ulam.’ Its scientific name is Cosmos caudatus. Therefore, it is also known as cosmos in English. This plant is indigenous to tropical America, and was introduced by the Spaniards into the Philippines, possibly because it was used by them as a vegetable at sea. Now it is pantropical, including Southeast Asia, where it is cultivated but also occurs in a naturalised state.

This erect, herbaceous plant can reach up to 2 metre high. It has grooved, purple-tinged stem with opposite leaf arrangement. The leaves are pinnatifid, and emit strong fragrance when crushed. The plant bears inflorescence at the tip of stem. The flowering stem is 5-30 cm long. The cluster of flowers consists of yellow tubular flowers and pink, spreading petal-like flowers. The inflorescence is slightly scented.

Culinary use

The leafy part of Ulam raja is commonly consumed with rice, budu, sambal belacan, tempoyak and cincalok. Its grassy taste is accentuated by a subtle peppery tinge. It is believed that by consuming this plant one can enhance his or her blood circulation as well as protect their bones.

Planting

It is good to plant it in pot or bed as the plant grows vigorously. Just sow the seeds at soil surface or fine texture mulch. It prefers sunny places and fertile, moist, well-drained soil. This annual is quite short-lived as it dies after flowering and seed production. However, the plant will self-sow and re-grow in the same plot.

Propagation: Seeds

ulam raja
Cosmos caudatus — The author is measuring the diameter of flower clusters.
Photo by Shang Ming

Benefits to biodiversity

The flowers of Ulam raja attract a variety of day flying pollinators. These include several species of butterflies such as Tawny costers (Acraea terpsicore), Chocolate albatross (Appias lyncida), Julia heliconians (Dryas iulia) and Sulphurs (Eurema spp.) as well as long tongued bees such as stingless bees and honey bees. As with most composite flowers, it likely harbours thrips as well.

As a low shrub, it also helps to provide shelter for small animals and create ground cover to protect against soil erosion. It can be planted in mixed beds with native plants, but because of its rigorous growth it has a tendency to crowd out other native plants.

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