Cosmos adds to a sunny garden in surprising ways

A group of bright pink Cosmos flowers

This photo of Cosmos bipinnatus was taken in my front garden in August, 2015.

The first time I saw cosmos in a blindingly sunny garden, orderliness was not the word that came to mind. No, barely contained chaos was more like it. The impenetrable thatch of tall stems thrust up cartoon-like flowers, in brilliant shades of pink, nodding in every direction. But the story goes that Spanish priests loved the evenly placed petals of this native Mexican plant and so dubbed it after the Latinized Greek word–kosmosmeaning good order.

There are actually 20 species of Cosmos but most gardeners are familiar with two annuals, Cosmos sulphureus and Cosmos bipinnatus. It’s easy to tell them apart. The big hint is in the name of Cosmos sulphureus. All flowers of this species are in the warm spectrum: yellow, orange and red. All Cosmos bipinnatus flowers are in shades of pink from blush to deep rose.

If you’re thinking of adding some cosmos to your garden (it’s not too late to score some plants at your local garden centre), keep these things in mind.

1. Don’t spoil them. Besides Mexico, cosmos is also native to parts of Central and northern South America and parts of southern United States. It’s also escaped and naturalized in places as far flung as the Caribbean, Italy, Australia, parts of Asia, South Africa and, yes, even Canada. But wherever this plant calls home, one thing is guaranteed. That home is going to be in a wide, open space with poor soil and not much shade–basically the farthest thing from virgin forest such as abandoned, over-grazed or fallow fields, the barren strips along railroad tracks or country roads and other neglected waste areas. Rich, fertile soil can actually make the plants become weak and leggy. In other words, if a dandelion thinks it’s a pretty good spot to settle down, chances are cosmos would agree.

A single cosmos flower against a plain white background2. Plant lots and plant close. Cosmos is a plant that proves there’s strength in numbers. Each plant appears quite fragile thanks to its long, slender stem and lace-like foliage. But as the plants grow up and out, those lacey leaves knit together to help support the group and become less susceptible to breakage from wind or rain.

3. You’ll help feed your garden’s wildlife and protect your other plants, too. Cosmos starts blooming around mid-June and will continue non-stop until frost, giving lots of winged critters a much needed banquet. Butterflies, including the Monarch, love Cosmos. Bees, too. The plants also attract parasitic wasps which help control pest insects.  Syrphid (hover) flies fuel up on Cosmos and then prey on aphids, scales, thrips and caterpillars. Lacewings are also attracted to Cosmos. This bug’s larvae destroy a host of pests, including aphids and mites.

4. Go au naturel or play up contrasts. Sure you can plant Cosmos at the back of the border and call it a day. But here are two ways you can really make the most of this gorgeous plant:

  1. If you stumbled upon cosmos in the wild, you’d probably find it surrounded by other leggy wildflowers and plenty of grasses. You can get that natural look even if you only have a small amount of space in your garden. Try a mixed planting of cosmos with tall sedges and other ornamental grasses for the look of a mini but magical meadow.
  2. Want to add drama to your garden? Place a bed of cosmos directly in front of a tall, clipped, dense hedge. In a sunny garden, the wispy stems and leaves and the bright flowers of the cosmos will pop against the dark, uniform backdrop created by the hedge.

One thought on “Cosmos adds to a sunny garden in surprising ways

  1. Pingback: Winners and losers at Landscape Ontario’s trial gardens | Ministry of the fence

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