Iris ensata Edens Paintbrush - Japanese Water Iris

Iris ensata 'Eden's Paintbrush', is a variety of rare Japanese water iris in cultivation, which is distinguished by the delicate colouring of its petals, as if hand-painted. Resembling large exotic butterflies immobilized in mid-flight, its flowers with gracefully trailing petals are completely speckled and veined with purple on a white background. They are adorned with a small yellow signal at the base of each sepal, designed to guide bees to the centre of the flower. Contrary to popular belief, this iris that thrives in flooded soil also grows well in borders, in good limestone-free soil that remains cool in summer, where they create wonderful displays. Iris ensata were once extensively cultivated in Japan, particularly around Edo (the ancestor of Tokyo), for cut flowers.

Iris ensata (synonym kaempferi), known in Japanese as hanashōbu, are better known as Japanese water iris, and have nothing in common with our classic garden irises, except for their membership in the Iridaceae family. The original Iris ensata is a fibrous rhizome plant native to Asia, specifically to the wetlands of Japan, the Himalayas, and Siberia. These irises, known to be difficult to cultivate, thrive in acidic and peaty soils (cannot tolerate excess limestone), require abundant water during their growing and flowering period, but appreciate slightly less damp soils in winter: they can be found in nature growing above the water level, which often decreases in winter and rises again in spring with the melting of snow.

The 'Eden's Paintbrush' cultivar forms an erect, bushy clump, reaching about 80cm (32in) in height when flowering (50cm (20in) for the foliage) with a spread of 40 to 50cm (16 to 20in). The plant slowly spreads on the ground through its rhizomes, becoming more beautiful year after year. The deciduous foliage, of a medium green colour, consists of long, narrow, sheathing leaves with prominent central veins. Flowering takes place between June and August depending on the climate, lasting for 3 weeks. Flower stems emerge from the clusters of leaves. Each stem bears 2 to 3 large flowers measuring 12 to 15cm (5 to 6in) in diameter. They are composed of 3 large, finely veined and speckled violet sepals on a white background, adorned with a bright yellow signal at the base, topped by 3 smaller and finer upright petals of a deeper violet. The centre of the flower is occupied by 3 petaloid styles of the same colour.

Often cultivated on the banks of ponds and basins, Iris ensata, like many marsh plants, can tolerate having their "feet" in water during the summer, but their rhizomes do not tolerate being submerged during winter, especially if it is icy. In our gardens, these Iris ensata will thrive in well-drained soil enriched with compost, but not drying out in summer. Plant them, for example, in heavy soil forming a slight depression, at the bottom of a slope, or on a bank where the soil is moistened by capillary action. Combine Iris ensata 'Eden's Paintbrush' with Anemone rivularis, daylilies, Darmera peltata, Lobelia 'Queen Victoria', Astilbes, Physostegia virginiana, Lysimachias, and Ligularias.