Iris ensata Comtesse de Paris - Japanese Water Iris

Iris ensata 'Comtesse de Paris', with its large flat flowers of pure white adorned with a small yellow macule, is a variety of Japanese water iris as elegant as it is bright. Unlike our garden irises, this rhizomatous perennial is comfortable in non-calcareous and waterlogged soils in summer. Superb when planted en masse in wet areas and on the banks of water bodies, the Iris ensata were once intensively cultivated in Japan, especially around Edo (the ancestor of Tokyo), for cut flowers.

Iris ensata (synonym kaempferi), hanashōbu in Japanese, better known as Japanese water iris, have nothing in common with our classic garden irises, except for their belonging to the Iridaceae family. The original Iris ensata is a fibrous rhizome plant native to Asia, specifically wet areas of Japan, the Himalayas and Siberia. These irises, known to be difficult to grow, prefer acidic and peaty soils (do not tolerate excess limestone), are thirsty for water during their growing and flowering period, but appreciate slightly less humid soils in winter: they are found in nature growing above the water level which often decreases in winter, then rises in spring with the melting of snow.

The 'Comtesse de Paris' cultivar forms an erect, rather upright tuft, reaching about 60cm (24in) in height when in flower with a spread of 40cm (16in). The plant slowly spreads on the ground through its rhizomes, beautifying year after year. The deciduous foliage, of medium green, is composed of long and slender ribbon-like leaves, sheathing at the base, marked by a prominent central vein. Flowering takes place between May and August depending on the climate, for a good 3 weeks. Flower stems emerge from the tufts of leaves. Each stem bears 2 to 3 large flowers measuring 12cm (5in) in diameter. They are composed of 3 large flat sepals, the base of which is adorned with a bright yellow signal, topped with 3 smaller and finer petals.

Often grown on the banks of ponds and basins, Iris ensata, like many marsh plants, can live with their "feet" in water during summer, but their rhizomes do not tolerate being submerged during winter, especially if it is freezing. In our gardens, these Iris ensata will thrive in a loamy soil enriched with compost, but not drying out in summer. Plant them for example in a heavy soil forming a slight depression, at the bottom of a slope or on a bank whose soil is moistened by capillarity. Associate the Iris ensata 'Comtesse de Paris' with Anemone rivularis, daylilies, Darmera peltata, Lobelia 'Queen Victoria', Astilbes, Physostegia virginiana, loosestrifes and Ligularias.