Cosmos flowers (Cosmos bipinnatus, C. sulphureus, C. caudatus or Mexican aster) are showy annual flowers that offer you SO many benefits. If you’ve never grown these ornamental beauties, you may be surprised how useful these cheerful flowers can be.
Cosmos Flowers
Cosmos is a member of the Compositae or Asteraceae family, just like their ‘cousins’: sunflowers, marigolds, yarrow, daisies, zinnias, lettuce and dandelions.
These easy care flowers are perfect for a full sun position in your garden or a pot, growing through spring to autumn.
Not surprisingly, the name Cosmos comes from the Greek word ‘kosmos’ which means ‘beautiful’. Aww! These flowers come in many colours and grow tall with attractive feathery leaves. I encourage you to find a pot or tiny space to sow a few seeds.
“Texture and foliage keep a garden interesting through the season. Flowers are just moments of gratification.”– Kevin Doyle
So why grow these beautiful blooms?
9 Benefits of Growing Cosmos Flowers
1. They attract bees, butterflies and other beneficial insects
Their open flowers provide easy access to nectar and pollen. You can never have enough pollinators and predator insects in your garden, helping pollinate and pest manage for you. Cosmos flowers are magnets for beneficial insects like lacewings, parasitic wasps, tachinid flies and hoverflies that feed on many pest insects and provide free pollination services.
2. They are easy to grow
Even in tough, hot or dry conditions with little water. They seem to flower best in poor soils with less organic matter which encourages lots of leaves at the expense of blooms. They are often seen growing along the road side in full sun, with no fertilizer in the soil and surviving on rain and dew. Perfect if you have a difficult climate!
3. You get free seeds and save money
If you want to save seeds, you need to choose cosmos varieties that have been open-pollinated rather than hybrids, and ideally organic. Why? This is important because otherwise they won’t grow ‘true-to-type’, so it’s a lottery what variety you will grow.
Hybrid plants do not give reliable results for seed saving. This is because they will either be sterile or the plants of the next generation may vary widely in their characteristics, uniformity and maturity.
Non-organic seeds are commonly sprayed with harmful fungicides and other chemicals and seedlings bought from nurseries may contain neonicotinoids, toxic to bees and other insects. Learn how to grow a pollinator-friendly safe garden here.
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It’s easy to save seeds from your own garden. When the cosmos blooms die and go brown, snip off the flower head. Holding a bag underneath, gently rub and shake the seeds inside. Now you have a handful of cosmos seeds you can scatter around your garden again or save until next season.
If you leave them in your garden, they will provide a free feed for your local birds.
4. These pretty flowers will self-sow
If you just allow your plants to die naturally, the dead flowers will fall to the soil. When the conditions are right, cosmos seeds will germinate all by themselves, saving you time seed raising. How awesome is that?
5. Long flowering and fabulous feature plants
Cosmos blooms can last many months, so they’re great value. When planted in a group, they are an attractive focal point and will attract more bees than just dotted around your garden as single plants. These clever insects know they use less energy flying from flower to flower for a free feed, when they’re all in one spot. Smart hey?

These flowers add beauty and colour to your garden, especially when planted en masse.
6. Edible flowers with medicinal benefits
If you grow from organic seeds and don’t use chemicals, the pretty petals of Cosmos sulphureus (C. bipinnatus, C. caudatus or Mexican Aster) are also edible and brighten up salads. One study* revealed Cosmos bipinnatus has significant antioxidant activity and a protective effect against oxidative DNA damage. White, pink and orange cosmos flowers had the best results. Antioxidant phytochemicals were found to inhibit free radical damage and help protect the human body from diseases. Another study* found both Cosmos bipinnatus and Cosmos sulphureus have properties that help protect the liver possibly due to the presence of quercetin and phenolic compounds.
7. Pests don’t seem to bother them
A low-maintenance flower without many pest problems is a bonus. Ideally, sow your cosmos in amongst other flowers like marigolds and nasturtiums, vegetables and flowering herbs. A diversely planted garden, even in a pot or tub will reduce the likelihood of an imbalance in pest insects.
8. Use as cut flowers in a vase or bouquet
These flowers can last up to 7-10 days if you re-cut the stems regularly and keep in fresh water. Ideally, cut your flowers in the early morning. This is when they contain the highest level of moisture, so are less likely to wilt.
Choose blooms with petals that are just starting to unfold. The flowers will open fully once the stems are in water. Plunge immediately into a bucket of warm water. Strip off any leaves on the lower part of the stem that will be under the water. Decaying leaves will quickly rot and reduce the vase life of your beautiful blooms. Enjoy them in your home or grow a bunch for friends.
9. Resilient even in drought
Whilst cosmos seeds need water to germinate so seedlings establish, I’ve noticed they flower even without regular watering. Perfect if you’re a neglectful plant ‘parent’ or live in a climate with little rainfall!
“In joy or sadness, flowers are our constant friends.” – Kakuzō Okakura
3 Tips for Growing Cosmos Flowers
- Plant in full sun in well-drained soil. Mulch well and protect from strong winds.
- ‘Deadhead’ regularly if you have time. Just pinch off the dry dead flower heads that contain the seeds. This helps encourage new growth and more flowers. Keep them in a sealed airtight bag in a cool dark place so seeds store longer.
- Depending on the variety and mature height of your cosmos flowers, they can grow quite tall. You may need to provide support stakes or sow beside a trellis or fence they can lean on.
If you’re looking for a beautiful, low-maintenance edible flower that attracts birds, butterflies and bees to your garden, with loads of benefits, try growing cosmos.
You may also like:
- 13 Benefits of Growing Flowers in your Vegetable Garden
- 5 Reasons to Grow Sunflowers
- How to Grow & Use Nasturtiums
- How to Grow Hydrangeas
References
- Antioxidative and Antigenotoxic Activity of Extracts from Cosmos (Cosmos bipinnatus) Flowers
- Chemical characterisation and hepatoprotective potential of Cosmos sulphureus Cav. and Cosmos bipinnatus Cav
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Kosmos is the Greek word for World. Kallos is the Greek word for Beautiful.
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I am somewhat confused. I read one statement and it says only certain colors are edible and the next does not mention colors. One article says they are edible and the next says no. I found the same to be true of Globe Mallow where one author says it is edible and the next says no. The other day I tried the Globe Mallow and I am still alive. What I found with the Globe Mallow is the flower has hairs on it and it did not want to leave the throat without the itching. The flavor was not to my liking but it is a pretty flower and does attract butterflies and bees so It is a keeper for me. I am doing my best to have a wild plant garden. What I also realize is the wild plants seem to have a higher concentration of vitamins than the things I buy in the store for salad.
Could you clear the confusion about the color of the Cosmos?
Hi Esther
There is some confusion (or lack of research) out there about edible flowers. Personally, I have read scientific studies on all 3 species of Cosmos as listed in this article and am satisfied they are indeed edible and have medicinal properties as well. For example, this paper on Cosmos bipinnatus.
Cosmos caudatus is well known in Thailand for its medicinal benefits.
I have been growing and eating cosmos flowers for some time, but obviously only growing them organically. I personally know edible flower farmers in my local area who sell their cosmos blooms to chefs and restaurants. I have not been able to find any information relating to flower toxicity – quite the opposite. I have the book “A Delicious Bunch” by Linda Brennan that confirms these 3 varieties are all edible.
Based on my research reading scientific papers and plant journals, I’ve not come across anything to suggest the colour of cosmos has any bearing on its edibility.
I hope you enjoy creating your wild plant garden! Cheers Anne
Hey, Anne. I didn’t know Cosmos were edible. That is cool. I planted some Cosmos Bright Lights, &, Cosmos Sensation Mix from seeds that I bought from my local Fred’s in town. The seeds came from Burpee. From Pennsylvania. Well, I know Nasturtiums are edible. They are pretty flowers. They have pretty Autumn colors. The foilage is cool too. Have a blessed, &, fun, &, peaceful gardening time.
Lisa
Hey, Anne. I planted some Cosmos Bright Lights from Burpee seeds. I bought them from the local Fred’s store in my town. I think that I planted them in late February, &, March of 2019. I also planted the Cosmos Sensation Mix light pink/dark pink. They bloomed up pretty. I didn’t know they were edible. I like Nasturtiums also. I know their edible. They have pretty Autumn colors. I like their foilage also. Have a blessed, &, fun, &, peaceful gardening season.
Lisa
I planted Cosmos seeds in small pots inside(to start them out) but packet does not say how often to water. Also, I live in Phx, AZ. Any special instructions for their health in ‘hell’? That’s how hot it can get here.
I just love Cosmos! They grew so well in California… just add water. I figured Houston, TX, with it’s tropical climate might not work. But I’m gonna give them a try.
And edible? After all these years loving this flower, I didn’t know it was edible either. Definitely gonna get some going in the Spring, here… Around the middle of January… LOL.
Thanks for the tips!
Jim B
Hi Jim
Cosmos are a perfect choice for Texas. They thrive in hot dry conditions! Perhaps try growing some in a pot to get started. Remember to start with organic seeds if you’re going to include the petals on your plate and avoid using any chemicals.
Happy gardening!
Anne
I didn’t know that cosmos flowers were edible Anne so I learned something new today. My grandmother always had cosmos in her garden. I dare say they self seeded from year to year. Consider me a new convert. I will be sprinkling some cosmos seed in the Sanctuary mix in the near future. Thank you for this lovely post 🙂
Thanks so much for the feedback Fran. I’m sure your grandmother (and lovely mum) would have allowed them to self sow. Much less work!
As I mentioned in the article, I always start with organic seeds especially if planning to eat the flowers. It’s not just a matter of GROWING organically, but also the source of the seed. They come in some many delightful colours – I have yellow in my garden at the moment and they are just SO cheerful. I must take some pics of the petals in a salad. They look so pretty in a vase of mixed blooms and herb flowers too. I’ve been arranging them with pineapple sage red blooms, dill and parsley flowers as I already have so many seeds, heliconias and some other flowering perennials. Like sunflowers, they just seem to make me smile!
Happy gardening. Anne