Sea holly

This sea holly is indispensable in Mediterranean-type gardens. The stems are an eye-catching steely blue, while the large heads of blue flowers sit above a soft frilly ruff of blue bracts in June. It's incredibly tactile and needs to be placed to the front of a border (but beware of other sea hollies which are incredibly prickly, and need to be kept well away from children). Provide it with poor, free-draining soil, and ideally a position at the foot of a wall where the soil doesn't stay soaking wet over winter. It has been given the Award of Garden Merit (AGM) by the Royal Horticultural Society.