Pinching Cosmos for More Compact Plants | Double Down! (2024)

Ever notice how some plants go all wild and leggy, like Cosmos if left to their own devices? Pinching cosmos may change your life – or at least your gardening experience!

We loved growing cosmos from seed in our flowerbeds last summer. Truth be told, the cosmos literally took over the space and grew vigorously but in a sprawling sort of way.

I’ve heard from numerous gardeners over the past few years who were in favor of pinching cosmos. This gardening tactic was new to me but I’m so glad I gave it a try!

What Are the Benefits of Pinching Cosmos?

Pinching cosmos removes the original growth point and encourages the plant to grow more densely.

Some benefits of pinching cosmos may include:

• More Compact Plants – Cosmos plants tend to be less leggy when you pinch off cosmos. Reducing the seedling’s original height diverts energy to branching instead. Cosmos grow fuller and denser.
  
• More Prolific Blooms – Pinching cosmos works similar to deadheading spent flowers. Since pinching signals branching, more flower heads will result as well.
  
• Two Plants for the Price of One! In many cases you can plant the tops of the cosmos that you pinch off, especially if you had leggy cosmos. Plant the pinched cosmos tops in moist potting soil and keep them under lights for a week or so. Soon you should notice that they’ve grown their own root system! Meanwhile, the bottom of the original plant should be branching and growing nicely.
  
• Stretch Your Seeds Further – Maybe you just bought a special pack of cosmos seeds to grow. Rather than blowing through all the seeds very quickly, you can make the most of your seeds by pinching cosmos into two separate plants.

How to Pinch Cosmos

Pinching off cosmos flowers is easy! It takes very little time and can produce big results. Get ready to double your blossoms and follow these simple steps on how to pinch cosmos.

1. Start with cosmos seedlings that are at least 6-8 inches in height.
2. Use scissors or your nails to pinch cosmos after the top three inches or so. Make sure to leave branches on both sides if you’re trying to double your flowers.
3. Water the original cosmos plant if needed.
4. Fill a starter pot (3” diameter or so) with potting soil. (I like Pro Mix!)
5. Use a pencil or the end of a paintbrush to poke a hole in the center of the potting mix.
6. Gently poke the pinched cosmo’s stem into the hole and gently pack the soil around the plant.
7. Use a spray bottle to moisten the potting mix generously.
8. Place the pot with the cosmos cutting under some grow lights to encourage a new root system.
9. Check for moisture and water as needed. After 5 to 7 days, new roots should grow from the pinched cosmo’s stem.
10. After the healthy new root system grows, you can harden off your cosmo plant and plant it outside in your garden!

Final Thoughts: Pinching Cosmos

Pinching cosmos encourages bushier plants with more flowers. The cosmos plants tend to be less leggy and not as sprawling.

When you plant the top portion of the cosmos you pinch, you can grow a brand-new plant! If you have a lot of garden space, this can really add up to double the flowers when you pinch the tops.

This was our first time pinching cosmos and I’m very happy with how the pinched tops grew into their own plants so easily.

I also had luck with a zinnia whose stem broke and I was able to get new roots to grow. I’ll definitely be trying this method again to rescue broken plants and to double the number of flowers we can grow.

Do you grow cosmos? Please share your experience pinching cosmos in the comments below and feel free to share other tips and ask questions. We’d love to hear from you!

05.05.22 – Updated to add photo of pink cosmos flowers.