Cosmos bipinnatus: Garden cosmos

Family: Asteraceae
Common name: Garden cosmos, Pink cosmos, Mexican aster

Garden cosmos plants can brighten up your garden inviting butterflies and honeybees in abundance, with their showy, bright petals. The plants can grow a height of about 1 meter with thick, soft stems that are covered with rough, white hairs, or can be completely hairless.

Leaves are green, thread-like, split into multiple segments about 8-10 cm long and 3-5 cm wide. Flowers are bright and showy with pink, red, purple, or white ray florets that are wider in the middle and lightly serrated towards the outer edges. Disk florets are tubular and yellow, with black anthers clearly visible among them.

Seeds are long, spindle-shaped, black, about 1 cm long, having short bristles at the tip. These seeds can be disseminated by furry animals or birds over short distances.

Seeds also fall around the parent plant producing tiny seedlings that might fight for space and nutrition unless they are replanted. Garden cosmos plants are weak and can topple once it produces flowers since the plants become top-heavy. But if they are grown together in clusters, the leaves will inter-link, giving the plant more stability and strength.

Garden cosmos plants prefer bright sunlight and well-drained soil. Heavy rains or flooding will cause the delicate stems to fall, or decay. Good fertilization and pruning can help these lovely plants to grow bushier, producing more flowers.

In tropical countries, these plants can bloom aggressively all through spring and summer, after which the plants die. The word Cosmos comes from the Greek word meaning beautiful, and bipinnatus comes from the pinnate, lace-like leaves.

These plants are very closely related to their yellow variants, Cosmos sulphureus or Yellow cosmos. There are many beautiful variants like Daydream, Early wonder, Candy stripe mix, Antiquity, Double click, Rubenza, Sonata, Velouette depending on the color of the flowers or the number of petals.

Garden cosmos plants are easy to grow and maintain, though they need regular watering, especially during the summer months. These plants do well as border or hedge plants, planted very close to each other in thick clusters.

Propagation is through seeds and stem cuttings. Seeds take 1-2 weeks to germinate, and the plants start flowering in 1-2 months.