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.

9 Reasons You Should Grow Cosmos Flowers

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.

Bee feeding on pollen in orange cosmos flower

Bee feeding on pollen in orange cosmos flower

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.

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.

Dried cosmos seeds on the flower head

Dried seeds on the flower head


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 (temperature and moisture), cosmos seeds will germinate all by themselves, saving you time seed raising. How awesome is that? If you’re looking for a plant to sell through easy propagating, this flower is ideal. If you don’t want the plants to self sow, then prune off the dead flowers.

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?

Cosmos add beauty and colour to your garden, especially when planted en masse.

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.

Arrange your cosmos in a vase with other blooms for a pop of cheery colour

Arrange your cosmos in a vase with other blooms for a pop of cheery colour

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

  1. Plant in full sun in well-drained soil. Mulch well and protect from strong winds.
  2. ‘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.
  3. 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.
Pink cosmos flowers growing against wooden fence for support

Pink cosmos flowers growing against a fence for support

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.

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© Copyright Anne Gibson, The Micro Gardener 2017. https://themicrogardener.com. All rights reserved.

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