Cut back eryngiums

Eryngiums, or sea hollies, will have lost their blue or silvery hues by now and will be standing brown and crispy in the border. You can leave them be as long as they look attractive and don’t flop or go mushy, which means they can provide shelter for insects or mammals over winter. But if you’re tidying up now to neaten borders or the plant is past its best, simply snip stems down to the base. The plant will soon grow anew in spring.