This is the perfect summer for Eryngium planum, and the difference between last year’s performance and this, is marked. In 2017 we had much more rain and not a lot of sun and my sea hollies produced too much lush growth, the stems flopped, and the effect was unremarkable. By contrast, this summer, the open, upright habit shows off to perfection a multitude of silvery blue flower heads (about the size of a thimble) with narrow bracts, and they are irresistible to bees, butterflies and other insects.
Sun and good drainage are key, as is low fertility, so they are especially happy in a Mediterranean or gravel garden, yet they look equally at home in an English cottage garden setting since they associate well with so many other plants.
In our garden, E planum occasionally self seeds, but it has a tap root and therefore strongly resists all attempts at being transplanted. At about a metre high, they are statuesque plants and last well into autumn, and as an added bonus, the airy stems make very good, and very long lasting, cut flowers.