Iris japonica

Iris japonica, also known as the fringed iris, is also called Iris of Japan, although it has nothing to do with  Japanese Iris (or kaempferi). It is a vigorous Asian species that spreads through rhizomes in semi-shaded areas. Its beautiful glossy, light green and vibrant foliage is decorative in winter and adorned in spring with small fringed, bluish-white flowers enhanced with gold, carried on graceful floral stems. Fringed iris easily establishes itself in a light understory, even if dry in summer, in regions which are not too cold. 

Iris japonica belongs to the family of Iridaceae, like all iris, and to the section of irises without beards. It is a botanical species native to China and Japan, where it colonizes rocky and grassy slopes and clear forests. The original form is Chinese, but a sterile form that does not produce seeds has been grown in Japan for a long time. Fringed iris can withstand temperatures as low as -12°C once established. It appreciates humus in the soil, and moisture in spring, but endures very dry summers quite well. 

It is a perennial, evergreen plant which forms a clump of long, flexible, sword-shaped leaves arranged in a fan shape. The clump measures between 50 and 60 cm (20 and 24in) high when flowering, 30-40 cm (12-16in) for the foliage. After a period of establishment, this iris spreads through long and thin rhizomes, which are very shallowly buried and can be easily removed to reduce their spread. They slip between rocks and under slabs and insinuate themselves among other plants. They flower from mid-March to June, depending on the climate. Late frosts can compromise this flowering. The green floral stems are thin and more or less branched. The flowers, are about 4 cm (2in) in diameter and consist of 6 spatulate tepals: 3 fringed white sepals spotted with violet-blue and gold, and 3 shorter and bluer petals. These flowers are solitary or grouped at the end of the floral stem.  

Fringed iris prefers shade and does not flower well in full sun. A permanent ground cover, attractive even in winter, in spring its delicate pastel flowers brighten shaded rock gardens, walls exposed to the northeast, or the base of hedges. In a dry understory, it can be associated with butcher's broom, greater periwinkle, or bigroot geranium. In slightly moister soil, it can be accompanied by less demanding ferns, bergenias, or nodosum geraniums.