Iris x hollandica Professor Blaauw

The Iris 'Professor Blaauw is a variety of Dutch Iris that was awarded in England in 1994 for its ornamental qualities and ease of cultivation. This bulbous iris produces large, brightly coloured flowers in late spring for 2 to 3 weeks. The flowers have a stylish shape and stand out for their elegance in the garden and in bouquets. This particular variety has two shades of sky blue and blue-violet, with a small golden spot at the center of each sepal.

Dutch Irises, or bulbous irises, have an underground storage organ in the form of a bulb, unlike their famous cousins, the Bearded Irises or Garden Irises. Belonging to the same botanical family as the Bearded Irises, the iridaceae family, they also differ by the absence of "beards," those pretty little fluffy and colourful tongues found on the drooping sepals of Bearded Irises. Dutch irises have never grown wild in Dutch soil, but are the result of cross-breeding between two main botanical species: Iris filifolia, sometimes confused with Iris xyphium which resembles it, both originating from Spain and North Africa, and Iris tingitana, from Tangier and northern Morocco. The genealogy of Dutch hybrids can sometimes be confusing, but the result is always remarkable. Their flowers, somewhat underutilized in the garden, are highly appreciated in floristry.

The 'Professor Blaauw' cultivar forms an upright and very narrow clump over time, reaching a height of 60 cm (24in) when in bloom. This perennial spreads indefinitely through the production of bulblets. It blooms in late spring, usually in May-June, for 2 to 3 weeks, on wind-resistant stems. Its solitary or paired flowers on the stems have a diameter of 8 to 10 cm (3 to 4in) and are relatively slender compared to those of Bearded Irises, but undoubtedly elegant. They consist of 3 upright, translucent, small petals in a celestial blue. Beneath this trio are 3 almost horizontal sepals, closely linked to the dentate petaloid styles on the edges, arranged in quincunx. Wider and spatulate, they are a vibrant blue-violet, illuminated by a beautiful golden spot. Each flower can live for 5 to 7 days, even in a vase. The bulb is round, 2 to 3 cm (1in) wide, covered with a fibrous tunic of rosy beige. It produces some linear, thin, and leathery leaves, somewhat resembling those of a grass, with a slightly glaucous green colour, often lightly striated and folded in half towards the ground. They often appear in autumn, persist to varying degrees depending on the severity of the winter, and dry up during the dormant period in summer.

Less known and less used by gardeners than Bearded Irises, Dutch Irises are nevertheless easy to cultivate in fertile soil and have undeniable elegance. Plant them in groups of 10 to 20 bulbs of the same variety: they will come back year after year to offer you more and more elegant and joyful flowers, which go well with the spring flowering of flowering shrubs. They also look stunning when planted among perennials such as peonies and daylilies, which will hide their absence in summer when they are dormant. Their Mediterranean origins give them excellent adaptation to summer drought. Finally, pick their flowers to make bouquets with roses, arums, lilies, or even late tulips. All irises need a sunny exposure to bloom well. Give them at least half a day of full sun.