Prickly Subjects

Eryngiums, more commonly known as sea hollies, are one of the most eye-catching garden plants, prized for their spiky, typically blue, thistle-like flowerheads, each one surrounded by a pointy ruff. The summer flowers are a magnet for pollinating insects, eventually fading to shades of buff in autumn and then providing interest as the weather turns cold and frost highlights the intricate detail of the architectural seedheads.

While a handful of perennial eryngiums are popular as border plants, this is a much more diverse genus than you might realise, as Kathy and Brian Pike, holders of the Plant Heritage National Collection, have discovered. “Over the years, as we’ve done more research and grown more plants, we’ve found that eryngiums come from a range-15°C in winter, might not seem the obvious place to grow plants with a reputation for loving sun-baked, free-draining soil – our native sea holly,, grows on beaches around the coast – but they now have the largest collection of these plants in the country.