BACKGROUND IMAGE: Narrow-leaved blue-eyed grass (Sisyrinchium bellum) growing in an alpine bed with stonecrop, auricular primula and thrift.

The blue-eyed grasses are a broad genus of New World flowering plants which include several garden-worthy perennials. Two that I have come to value are the ground-hugging S. bellum (background photo) and the taller S. striatum (illustrated here).

Despite their common name, they are not grasses, but actually members of the iris family (Iridacae), which is evident in their sword-like foliage. Their penny-sized starry flowers, however, are quite unlike irises, opening in succession for many weeks in the summer.

I like these Sisyrinchium for their architectural structure and quirky botanical details, but also for the strong splash of colour they add to the summer border.

Although there are hundreds of species, only a dozen cultivars are commonly available, but among those you can find a range of colours including blues, purples, white, yellow, and pinkish-browns.