Iris bulleyana - Iris de Bulley, Iris sino-sibérien

Iris bulleyana is an Asian botanical iris with blue-violet flowers traversed by fine purple veins around a creamy white to pale yellow zone. They rise above narrow, green foliage with a slightly glaucous underside. Unlike bearded irises that thrive in dry soil, this species requires soil that remains moist during its growing season, and drier in winter. Very hardy, it can be grown in full sun or light shade, in a moist border, a damp meadow, or on the non-submerged bank of a pond. Rarely planted in gardens, it will appeal to enthusiasts of botanical irises and collectors.

This iris belongs to the Iridaceae family and the series of Sino-Siberian irises. It is a herbaceous, rhizomatous perennial: its underground rootstock produces new leaves each spring and slowly expands to form a dense clump. The foliage generally dies back in winter, but may partially persist in mild climates. This species grows naturally between 2,300 and 4,300 m altitude, in damp meadows, on cool slopes, and along streams in Sichuan, Yunnan, Tibet, and Myanmar. This montane origin explains both its cold hardiness and its need for cool conditions. Bulley's iris was described in 1910 by the British botanist William Rickatson Dykes. Its name honours Arthur Kilpin Bulley, founder of Bees Nurseries and patron of several botanical expeditions to Asia.
The rather slender rhizomes produce linear leaves 30 to 45 cm long, green on top and more glaucous underneath. Hollow, erect, and sparsely branched stems rise to 60 or 80 cm and bear one or two flowers. These measure 6 to 8 cm in diameter. As with all irises, the flower has three upright floral parts and three trailing ones. The upright parts are narrow, blue-violet to lilac. The trailing sepals, broader, show a violet tip and a pale central zone, veined or dotted with dark blue to purple. This iris is beardless, unlike German irises. Flowering occurs from late May to July depending on the climate. It is more abundant in full sun, provided the soil does not dry out. After flowering, elongated capsules containing brown seeds may form. This plant tolerates heavy soils if they are aerated and rich in organic matter. It prefers neutral to slightly acidic soil. Its rhizomes tolerate significant moisture during the growing period but risk rotting in waterlogged soil in winter.

Iris bulleyana will thrive in a cool, rainy oceanic climate in summer, or in a mountain garden on non-calcareous soil. It can be planted on a bank that does not become flooded in winter, as well as in a border where the soil does not dry out in summer. Primula beesiana flowers at the same time in purplish-pink tones and shares its moisture requirements. An Astilbe ‘Washington’, with white plumes, takes over in early summer in a slightly shaded spot. In very moist soil, Caltha palustris var. alba provides earlier flowering by the water's edge. This iris can also join a collection of Asian species alongside Iris chrysographes Black Knight, with almost black flowers.