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Polyommatus icarus

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Although the common blue butterfly is widespread and its conservation priority is classed as low, in places around the UK there are local declines in its range – and Wanstead is an example of that. Locally, the best places to see it are areas of unmown grassland in Wanstead Park and on Wanstead Flats, but numbers in both locations have declined. Frequent mowing of grass removes the wildflowers on which the caterpillars and adults alike feed.


  • Plant birds-foot trefoil and white clover in your garden for caterpillars – they’re pretty wildflowers that will tumble out of pots or can help spread over paving to green it up. 

  • Lift plastic grass / paving slabs and replace with a lawn. Go no-mow in spring and summer to encourage wildflowers.

  • Create a beautiful 'Butterfly Border' packed with flowers loved by the adult insects. Find out how

  • Use the edges of your garden to create a habitat where caterpillars and other insects can shelter during winter. Grow ivy over fences – it’s a wonderful plant for wildlife – or add a row of native shrubs along your boundaries. 

  • Never use pesticides or weedkillers in your garden. Instead, aim to attract lots of different wildlife to keep things in balance, using biological pest control if necessary. Lobby the council to stop spraying pesticides around our streets.

  • Reduce light pollution by ditching unnecessary night lights in your garden - it is thought to be contributing to the dramatic decline in insects.