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How to collect seeds & winter sow Mountain Cornflower (Centaurea montana)

Mountain Cornflower (Centaurea montana), also known as perennial cornflower or bachelor's button, is a striking perennial that captivates with its vivid blue flowers. This hardy plant is a great addition to any garden, offering both aesthetic appeal and ease of care. In this post, we'll detail how to collect seeds from Mountain Cornflower and guide you through the winter sowing process to ensure a flourishing display in your garden next spring.

Mountain Cornflower thrives in a variety of soil types but prefers well-drained soil. It flourishes in full sun to partial shade and is tolerant of both dry and moist conditions. This perennial is well-suited for USDA hardiness zones 3-8.

  • Height: Typically reaches 18-24 inches (45-60 cm).

  • Flowers: Produces vibrant blue, fringed flowers.

  • Bloom Time: Blooms from late spring to early summer, with the possibility of a second bloom in late summer.

  • Foliage: Features lance-shaped, gray-green leaves that provide attractive foliage even when not in bloom.

How to collect Mountain Cornflower seeds

Seed collection for Mountain Cornflower should be done in late summer to early fall, after the flowers have withered and the seed heads have dried.

You'll need...

  • Sharp scissors or pruners

  • Paper bags or envelopes

  • Labels and a pen

  1. Identify Mature Seed Heads: Look for dried, brown seed heads on the plant.

  2. Harvest the Seed Heads: Use scissors or pruners to cut the seed heads from the plant carefully.

  3. Store the Seed Heads: Place the seed heads in a paper bag or envelope, and label them with the plant name and collection date.

  4. Drying: Allow the seed heads to dry in a cool, dry place for a few days to ensure the seeds are completely mature.

  5. Extract the Seeds: Once dry, gently break open the seed heads to release the seeds. Separate the seeds from the chaff using a sieve or by gently blowing away the debris.

  6. Store the Seeds: Store the seeds in a labeled envelope in a cool, dark place until you're ready to sow them.

How to winter sow Mountain Cornflower

Winter sowing is an excellent technique for perennials like Mountain Cornflower, replicating natural germination processes.

Here are a few of our favorite ways... and the way that we actually winter sow every year in our Danish garden.

Materials Needed

  • Clear plastic containers with lids (e.g., milk jugs, large yogurt containers)

  • Potting soil or seed starting mix

  • A drill or knife (for making drainage holes)

  • Duct tape

  • Labels and a pen


  1. Prepare Containers: Clean the plastic containers and cut them around the middle, leaving a small hinge. Make drainage holes in the bottom using a drill or knife.

  2. Fill with Soil: Add about 3-4 inches of potting soil or seed starting mix to the bottom half of the container. Moisten the soil until it is damp but not soggy.

  3. Sow the Seeds: Sprinkle the Mountain Cornflower seeds on the soil surface. Lightly press them into the soil but do not cover them, as they need light to germinate.

  4. Seal the Containers: Close the containers and secure them with duct tape. Label each container with the plant name and the date of sowing.

  5. Place Outside: Position the containers outdoors in an area where they will be exposed to winter weather but protected from strong winds. The seeds will experience natural stratification, benefiting from the freeze-thaw cycles of winter.

  6. Monitor Moisture: Check the containers periodically throughout the winter to ensure the soil remains moist. In early spring, keep an eye out for germination signs.

By following these steps, you can successfully collect seeds and winter sow Mountain Cornflower, ensuring a beautiful and robust garden display. This method is both cost-effective and gratifying, allowing you to cultivate plants from seeds you've collected yourself. Happy gardening!

We encourage you to share your experiences or any additional tips you have for growing Mountain Cornflower in the comments in the YouTube video. Connecting with fellow gardening enthusiasts can provide valuable insights and inspiration!


Welcome to my garden

Hi! I'm Lars (Denmark).

Thanks for joining me as I share tips and inspiration for perennial gardening. 

Click below to see what's growing in my garden right now? 

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