By: Justin Butts
Cosmos are the ideal flower for summer gardens in the Coastal Bend. They are drought-tolerant, can take a lot of heat, and don’t mind poor soil. Best of all, the flowers are absolutely gorgeous! What more could you ask?
Cosmos are annual plants (frost kills them) native to Mexico. Spanish conquistadors discovered the flowers when they met the Aztecs, and sent seeds home to Spain. Spanish friars, marveling at the perfectly ordered structure, named the plant “cosmos” after the Greek word for an ordered universe – or harmony in the heavens.
Cosmos, like marigolds, tomatoes, peppers, and many other plants native to Mexico, did not find their way to the U.S. for several centuries.
The English colonies in America were not allowed to trade with Spain, so they had no access to the foods and flowers that grew on their southern doorstep. Cosmos traveled to Spain, where their cultivation spread to warmer climates. Around 1700, the wife of the British ambassador to Spain brought cosmos seeds home to England. Another 50 years later, the first cosmos seeds finally made their way to America.
Under ideal conditions, some cosmos varieties can grow to six feet tall. In the Coastal Bend, most varieties grow to about three feet tall. Do not fertilize, as this decreases flower growth and causes the stems to grow thin and spindly. Also, do not overwater. If blooming slows, ease off the watering until the flowers brighten and grow more vigorous.
Plant cosmos at the back of the flower bed, preferably against a fence, for structure to help hold the tall stems upright. For potted plants, look for “Sonata” or “Dwarf” varieties.
Cosmos require little care once they are established. When cutting blooms for bouquets or deadheading, cut off the top third of the stem. This pruning invigorates the plants. With proper care (meaning not much!), your cosmos that survive the August heat should bloom beautifully all the way to the next frost.
Plant in full sun in well-drained soil. Grows easily from seed, but takes up to 21 days to germinate, so bed can get weedy. If planting by seed, till the soil and immediately sow seeds at 1/4” depth. Thin flowers to 12” spacing. Or, plant transplants at 12” spacing with native leaf mulch covering soil. No fertilizer, which causes leggy stems with poor blooms. After initial bloom, cut off all flowers to promote growth. Cut top third of stems when deadheading. No pests.
When buying seed packets or nursery transplants, the varieties Sensation (gorgeous pink flowers) or Picotee (white flowers with purple or reddish edges) grow tallest, up to 3’ or more in height. The Sonata varieties are richly colored and shorter, perfect for pots. The varieties Klondyke and Ladybird Dwarf are also shorter and come in shades of orange, red, and yellow. Space shorter varieties at 10” for denser plantings.
Cosmos are a beautiful summer bloom that look great in gardens or fresh cut bouquets. They come in a variety of colors, making them a versatile flower for nearly any arrangement. From fresh picked bridal bouquets to birthday arrangements, the options are endless! Though the petals look fragile, they’re actually pretty hardy and grow to be very tall. Their height and blooms make for a fun and whimsical addition to centerpieces. They give off a cute “tea party in the garden” vibe and even look beautiful in a vase all by themselves!
– LaToya Rodriguez, @rosesoireecctx
Cosmos have long been used in Mexico and South America to treat malaria. They contain quercetin, a flavonoid with antioxidants that are believed to help treat respiratory infections. The science is still inconclusive, but researchers hope this natural treatment can help. Bonus points if the flowers in our garden can help defeat illness!