How to Propagate and Grow Centaurea?

Centaurea, Knapweed, originate from Europe and Asia and are a genus of annual and perennial summer flowering gardening plants.

There are around six hundred species within this genus.

Attractive lance shape leaves are greyish green.

Flowers are solitary and thistle or daisy like.

Flower colours range from white, blue, rose, yellow to purple.

Many species grow naturally in woodlands and meadows.

Some species of Knapweed are considered to be invasive weeds in some regions.

Essential info

Genus: Centaurea
Family: Asteraceae
Species: Cyanus
Common Names: Knapweed, Black Knapweed.
Classification: Hardy annual and Perennial.
Height: From around 30cm to 90cm (12in to 36in).
Flowering: From late spring to autumn.

Where to Grow?

Ideal for grouping in beds and borders.

Centaurea are one of those gardening plants that are good to have in any planting arrangement.

They perform well and not only give colour to most planting schemes but also give texture and structure as well.

They make excellent cut flowers.


They prefer full sun, they thrive in it!


Any free draining soil.

Propagation info

  • By seed in early to late spring.
  • Seed sowing outdoors achieves best results.

When and Where to Sow ?

Outdoors early to late spring.


  • Silver sand (if you are marking out the sowing area).
  • Empty and dry used plastic water/lemonade bottle (to use for holding the silver sand if you are marking out the sowing area).
  • Labels.
  • Watering can.


Garden rake.

Sowing Your Seeds

The area where you intend sowing your Centaurea seeds should have been previously prepared.
(Dug over and fertilised at the end of the last season).

Make sure you remove all weeds and large stones. Rake over the surface of the soil until you have a nice fine tilth.

Now you can scatter sow or sow in individual areas.

For scatter sowing just scatter the seeds where you want your them to grow.

Sow the seeds thinly and lightly cover them with soil using your rake.

For individual sowing mark out the sowing area with you silver sand, from the plastic bottle, and thinly sow the seeds within the marked area.

All you have to do then is lightly cover the seeds with soil using your rake.

Whether scatter sowing or area sowing after covering your seeds with soil make sure you label the area with plant type and sowing date.

And of course don’t forget to carefully water the seeds in. Use your watering can with a *fine rose, turned upside down, and gently water the areas you have sown.

Do not flood the area or have the watering can too high, or your seeds will be washed away and uncovered.