Keep your eyes peeled for common knapweed this summer

Each month we are sharing a local plant species to highlight the wealth of nature and biodiversity that we can enjoy here in Brighton & Hove.    

This month we are putting the spotlight on common knapweed, also known as Centaurea nigra, lesser knapweed, or black knapweed. 

Common knapweed  

This stunning thistle-like wildflower has vibrant pink-purple flower heads and can reach up to a metre in height. Common knapweed flowers from June to September and really brightens up the later summer flowering period. It grows on all kinds of grassland habitats, including chalk downland, woodland, clifftops, lawns, and roadside verges.  

Common knapweed provides a massive boost of nectar for our pollinators – in fact, it was found to be among the top 5 species for nectar production in a survey of UK plants.  

This means it feeds all kinds of hoverflies, beetles, bees, butterflies and moths, such as common blues, marbled whites, meadow browns, adonis blues and dark green fritillaries.  

A photo of common knapweed

Finding common knapweed in Brighton & Hove 

You can easily spot common knapweed on verges throughout the city, and in parks and open spaces such as Sheepcote Valley and Wilding Waterhall.  

Adapted to urban landscapes 

Cheyenne Plant, Sustainability Officer r at Brighton & Hove City Council, said: “Many of the plants we see as weeds play a crucial role for biodiversity by providing food and offering shelter for insects, birds, amphibians, reptiles, and mammals – linking the food web together.  

“These plants are perfectly adapted to live in our urban landscapes on our chalky soils, and can help other plants to thrive by fixing nutritional imbalances in soil.   

“Common knapweed is a great example of this. It’s a hardy species that is rich in nectar and pollen which forms an important part of our natural ecosystem here in Brighton & Hove.”  

Biodiversity in Brighton & Hove  

Biodiversity is our planet’s life support system. Restoring nature underpins the health and wellbeing of people and wildlife in an era of climate change.  

Discover how you can play your part in protecting biodiversity and open spaces

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