Cosmos – October birth flower

Cosmos (Cosmos bipinnatus) is a warm weather annual flower.   Their daisy like blooms make great cut flowers.  The flower colors most available in garden centers tend to be in shades of pink, red, or white. Other colors like yellow, orange, and bicolor are often only available by seed packets. One variety (on my wish list) is called ‘Chocolate Cosmos’ with dark red flowers that smell like chocolate.   I’ve only seen this in seed packets.

Cosmos are tall airy sprawling plants with fine feathery foliage. They thrive in full sun, hot weather, and not bothered by heat or humidity.   They are very drought tolerant once established and don’t like a lot of water.  They also prefer a poor soil quality. A high nutrient soil often leads to lots of foliage and not a lot of flowers.

Their heights range from 1 to 6 feet and many of the plants in garden centers are in the 3 to 6 foot range.   Tall varieties are best for the middle to back of the borders, especially if they get support from other nearby plants.   Their thin sprawling stems make them difficult to stake.

They can be direct seeded in the garden in a full sun, well drained location.  Nighttime temps should be regularly in the 50s.   The seeds can also be started indoors.  Make sure the seeds or plants are planted after danger of frost is past and the soil has warmed up. Note that these plants will reseed in the garden.

Cosmos can be affected by aphids, thrips, aster yellow and powdery mildew.  Space the plants about 10 to 12 inches apart for good air circulation. 

The only maintenance with this annual flower is the regular deadheading.   The plants need to be deadheaded throughout the season to keep the blooms coming.