Iris ensata Dinner Plate Sundae - Japanese Water Iris

Iris ensata Dinner Plate Sundae is a variety of Japanese Iris from the "Dinner Plate" series that offers particularly large flowers, the size of a dessert plate. 'Sundae' produces flowers in May and June that are flat, with barely wavy white petals, widely veined with intense violet, and with bright yellow signals in the centre. It should be grown in non-calcareous and waterlogged soil in summer.

Iris ensata (also known as 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 for being difficult to grow, prefer acidic and peaty soils (they do not tolerate excessive limestone), are thirsty for water during their growth and flowering period, but appreciate slightly less humid soils in winter: in nature, they are found above the water level, which often drops in winter and rises again in spring with the melting of snow.

The cultivar 'Sundae' is a recent horticultural creation from the "Dinner Plate" series, which gathers varieties with oversized and remarkably colourful flowers. This variety forms a clump of bristly, rather upright vegetation composed of fine leaves. The plant will reach about 60 to 70 cm in height when in flower, with a spread of 50 cm. This iris slowly spreads on the ground through its rhizomes, becoming more beautiful year after year. The deciduous, medium green foliage consists of long and slender ribbon-like leaves, sheathing at the base, marked by a prominent central vein. The non-repeating flowering occurs in summer, earlier or later depending on the climate. Floral stems emerge from the clumps of leaves, each carrying 2 to 3 very large flat, 15 cm diameter flowers. Each flower is composed of large, flat, and horizontal sepals, with pronounced waves, topped by slightly smaller petals and 3 erect styles. Bright yellow signals illuminate the centre of the flower.

As waterside plants, Japanese irises can live slightly submerged in water during the summer, but their rhizomes do not tolerate this situation during winter, especially if it is freezing. In gardens, Japanese irises will thrive in loamy soil, lightened with compost, but one that does not dry out in summer. For example, plant them in heavy soil forming a slight depression, at the bottom of a slope, or on a bank where the soil becomes moist through capillarity. 'Sundae' can be accompanied by Anemone rivularis, Darmera peltata, and astilbes along the edge of a pond. Caltha palustris or Euphorbia palustris echo the yellow signals of the Iris. In constantly moist soil, consider loosestrifes and ligularias, for example.

Beautiful when planted in large masses in wet areas and on the banks of water points, Iris ensata were once intensively cultivated in Japan, particularly around Edo (the ancestor of Tokyo), for cut flowers.