Add Harmony to your Garden with Cosmos

COSMOS

“Cosmos” is the Greek word for harmony or ordered universe and is directly opposite of “chaos,” which is how one might describe the riotous explosion of color these attractive flowers bring to the home landscape.

Want to add a splash of color and bring harmony to your garden. Plant cosmos, with our tips: https://gardenerspath.com/plants/flowers/grow-cosmos/

Spanish priests in Mexico named these cheery little blooms because of their evenly placed, orderly petals.

Indeed, the plant’s pink, red, white, lavender, orange, or chocolate petals are beautifully spaced around a (usually) yellow central disk.

Big Family Reunions

These plants belongs to the huge Asteraceae family, and are cousins of daisy and marigold. Of the 20 or so species of cosmos, two are most commonly grown in home gardens: C. sulphureus (sulphur and yellow cosmos, Mexican aster) and C. bipinnatus (common and garden cosmos and also – because, of course – Mexican aster).

White Cosmos | GardenersPath.com
Photo by Lorna Kring.

C. sulphureus is native to Mexico, Central America, and northern South America. It has naturalized in most other parts of the world. C. bipinnatus, also native to Mexico, has found its way into most corners of the globe, as well.

Sulfur Cosmos | GardenersPath.com

These pretty flowers liberally reseed – to the point where they are sometimes referred to as weeds. In the event that you have too many blooms, cut the flowers and put them in vases.

Hot, dry conditions, along with poor to average soil, are optimum conditions for this plant. Usually grown from seed, you may also find starts at a nursery.

How to Grow Cosmos | GardenersPath.com
Photo by Lorna Kring.

In most parts of the United States, this plant is considered an annual, though gardeners in zones 9 and 10 may find them to be perennial.

And with a long growing season, they add vibrant color to the autumn garden.

Tips for Growing Cosmos | GardenersPath.com

They also make a great choice for children’s gardens and novice gardeners thanks to their easy and quick growth habits.

A Rainbow of Choices: Where to Buy

You’ll find a wide variety of cultivars and mixtures available from seed suppliers. For a brilliant red, orange, and yellow collection of C. sulphureus, try this packet of 500 seeds from Mountain Valley Seed Co., available via True Leaf Market.

Cosmos Cosmic Mix | GardenersPath.com

Cosmos Cosmic Mix

These plants will reach about 12 inches tall and produce semi-double, 2- to 3-inch flowers that bloom throughout the season.

Or, choose classic cosmos in a rainbow of colors in this seed mix from David’s Garden Seeds, available via Amazon.

Crazy for Cosmos Mix

You’ll get 10 open-pollinated varieties in this mix of 500 seeds that will grow from 45 to 54 inches tall.

David’s Garden Seeds also offers a stunning deep red variety, also available on Amazon. ‘Tetra Versailles Red’ flowers open wine-red and gradually fade to a bright pink.

Cosmos ‘Tetra Versailles’ Seeds

You’ll get 500 non-GMO, hand-packed seeds that produce 2- to 3-foot plants that bloom in about 80 days.

Avoid the Flop

This low-maintenance plant tolerates fairly poor, well-drained soil with a pH between 6.0 and 8.5. You don’t want to fertilize much because you’ll end up with lots of foliage and not many flowers.

Sow seeds outdoors at a depth of 1/16 inch, or indoors five to six weeks before the expected date of last frost.

Grow Gorgeous Cosmos | GardenersPath.com
Photo by Lorna Kring.

These 1- to 6-foot-tall plants can become top heavy and floppy, so plant them in masses and they’ll support each other.

These cosmic gems flower best in full sun, but the plant will tolerate a bit of shade. It requires only a moderate amount of water.

Plant tall varieties at the back of borders or as a central focal point, and use smaller varieties as mid-sized plants in mixed beds.

Grow Cosmos with These Tips | GardenersPath.com

For planters and containers, make sure to use dwarf varieties. Full sized specimens will crowd out the other plants, and their roots will dominate available soil.

Deadhead spent flowers to encourage more blooms, but leave some in place to develop seeds – they’re a favorite of visiting winter birds!

The Usual Suspects

This Asteraceae plant family member can be plagued by aphids and thrips.

For both of these pests, try insecticidal soap, such as this one from Garden Safe, available via Amazon.

Garden Safe Houseplant and Garden Insect Killer, 24-Ounce Spray

Also look out for aster yellows and powdery mildew.

The only cure for aster yellows is prevention. Use diatomaceous earth or insecticidal soap to kill the insects that spread the bacterial disease. Plants infected with aster yellows must be pulled up and destroyed.

Safer Brand Garden Fungicide, 24 Ounces

Treat powdery mildew with a fungicide, such as this one from Safer Brand, available via Amazon.

A Little Order, A Lot of Beauty

If your garden universe doesn’t include this worldly annual, perhaps it should. This easy-care plant thrives on sun and heat, offering glorious color in return.

Look for seeds online, plant indoors a few weeks before the last freeze, or outdoors in early spring. Keep diatomaceous earth and insecticidal soap on hand and you’ll be set.

Add Harmony to Your Garden with Cosmos | GardenersPath.com
Photo by Lorna Kring.

Are cosmos growing in your garden? In the comments section below, tell us about your experience with this galactic favorite. And learn about another Asteraceae family member in this article about Swan River daisy.


Don’t forget to Pin It!

A collage of photos showing pink and orange cosmos flowers in bloom.

Photos by Lorna Kring, © Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Product photos via True Leaf Market, David’s Garden Seeds, Safer Brand, and Garden Safe. Uncredited photos: Shutterstock. With additional writing by Lorna Kring.

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About Gretchen Heber

A former garden editor for a daily newspaper in Austin, Texas, Gretchen Heber goes through entirely too many pruners and garden gloves in a year’s time. She’s never met a succulent she didn’t like and gets really irritated every 3-4 years when Austin actually has a freeze cold enough to kill them. To Gretchen, nothing is more rewarding than a quick dash to the garden to pluck herbs to season the evening meal. And it’s definitely time for a happy dance when she’s able to beat the squirrels to the peaches, figs, or loquats.

2 thoughts on “Add Harmony to your Garden with Cosmos”

  1. Hello Gretchen, I love flower gardening. I always spend some time with my garden and family. I always teach my kids about gardening. You have such a beautiful garden. Thanks for sharing this post.

  2. Hi Jane! Thank you for reading and taking the time to comment! I’m so glad you’re sharing your passion for gardening with your children…. it’s important we pass our love of the Earth on to the next generation, don’t you think?

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