Cosmos, flower of harmony
One of the prettiest garden plants are cosmos, which are easy to grow in either partial sun or, preferably, full sun. A native of Mexico, the daisy-like flowers come in a variety of colors and species.
Given its genus name ‘Cosmos’ by Mexican priests, the derivation of the word is from the Greek word ‘Kosmos’, meaning ‘order’ or ‘harmony,’ reflecting its evenly placed petals. Representing the birth month of October, it blooms continually during summer and fall, easily thriving in well-drained soil without much soil preparation needed.
Lacy, simple pinnate or bipinnate leaves surround a long slender stem on both sides. Flowers are delicate and solitary with a single row of petals and yellow center. As the stems are tall and slender, strong winds may cause bending, so staking them might be necessary.
There are over 25 known species of cosmos, including various cultivars and varieties. The yellow species, C. sulphereus, is native to our meadows and grasslands and can range in height from 4 to 7 feet. According to Utah State University, cultivated varieties include “Crest Red,” “Lady Bird Dwarf,” and “Klondike.” Cosmos bipinnatus is a mix of purple, pink and white flowers, 1 to 6 feet in height. Cultivated varieties include “Candy Stripe Mix,” “Daydream” and “Gazebo Mix.” Listed also is the dark purple-brown flower called “Chocolate,” with a unique chocolate fragrance!
After all danger of frost has passed in spring, seeds can be scattered and lightly raked, germinating in seven to fourteen days. The soil should be kept moist until they emerge, then water less often, but deeply. Fertilization or composting is not necessary as cosmos will thrive in poor soils. Spacing each seed 1 to 2 feet apart will help avoid aphids, gray mold and powdery mildew, promoting adequate air flow. Deadheading will encourage reblooming, but trimming the plants 12 to 18 inches will limit seed production.
Cosmos plants will reseed themselves, dropping their seed in the soil and producing the next generation if adequate room is provided. Few common plant diseases affect cosmos, which adds to the beauty of a pollinator garden.
Seeds can also be saved, dried and stored throughout the winter if preferred. Blooms need to be dried away from light and stored in a moisture tight container in a cool, dark place. They can be started in pots in spring four to six weeks before the last frost, then planted in a sunny location.
Enhancing gardens as a border annual, cosmos presents itself well in floral arrangements. Bees, butterflies, finches and other beneficial insects are attracted to cosmos, adding to the perfect habitat.
This is one pollinator plant that will enhance any garden as a backdrop against a fence or behind shorter plants, adding height, interest and beauty.
Kane Shipka is an Ohio State University Extension Master Gardener Volunteer in Mahoning County.