Authors: RNDr. Pavel Sekerka, Ing. Markéta Macháčková, Mgr. Milan Blažek
Irises from Sibericae Section
This section irises are clumpy plants with short bifurcated rhizomes. Foliage turns brown in autumn and retracts; young leaves forms in fall and sprout in spring. Stem is leafless, single or branched. Capsules are oval or round triangle in diameter without ribs.
Significant Botanical Species
Iris forrestii Dykes – Yellow Iris or Forrrest's Iris
Plants reach 40cm. Stem doesn’t branch and caries 1-2 flowers. They are pure white, sepals upright, petals with tiny brown spots at base. Spathes are herbaceous. It comes from South-West China.
Iris chrysographes Dykes – Black Iris
Height 45cm, bracts herbaceous, leaves shorter or same size as stem. Flowers are mostly dark purple to almost black with yellow (not white) spots along petal veins, sepals are inclined. It comes from Himalayas.
Iris sanguinea Hornem. – Blood Iris
According to plant population the height can be 40-70cm. Stem is single with two flowers, spathes green, and leaves shorter than stem. Flowers are blue with significant veining, petals have brown reticulate pattern on yellow (white) background and sepals are upright. It grows from Baikal to Korea and Japan.
Iris sibirica L. – Siberian Iris
They can be 50-110cm tall with branched stem, each carrying 2-5 flowers. Spathes are dry, membranous, and leaves shorter than stem. Flowers are violet or rarely white. It grows in a large area from Central Europe to Baikal.
Breeding of Siberian Irises
Garden cultivars have their origins in two species: Siberian Iris (Iris sibirica) and Blood Iris (Iris sanguinea). The second one has a couple of larger flowers on a stem without branches. Both species have identical chromosome count 2n = 28 and that is the reason they hybridize so easily. Other botanicals in this group have chromosome count 2n = 40 and they cannot hybridize with Siberian Iris. For example yellow color of garden cultivars doesn’t come from Iris forrestii or I. wilsonii (which have yellow flowers) but it is an enlargement of yellow basal spot of Siberian Iris.
Siberian irises are known in a culture in England since 17th century, which is the same time of introduction of Iris sanguinea into Japanese gardens. First garden cultivars are know since the beginning of 19th century: white flowering Iris sibirica ´Alba´ was introduced in 1809, dwarf ´Acuta´ in 1814 (mentioned in checklist as I. acuta Wild., 1814 and as I. sibirica ´Acuta´ in 1840) and at last I. sibirica ´Flore Pleno´ in 1852. Until 1900 there were only 11 cultivars known. A big turning point in breeding was introduction of Iris sanguinea. It was brought to England by Peter Barr in 1900 and very slowly new cultivars started appear. On of the most significant breeders of this era was American Frances Cleveland, who registered 40 cultivars by the year 1938 (e.g. ´Sunnybrook´, ´White Dove´, ´Blue Ridge´). After World War II another American Lady stepped in, Elizabeth Scheffy has bred lavender color and reblooming. For instance: pink iris ´Pink Allure´, (Scheffy, R. 1953) or purple one ´Blue Moon´ (Scheffy, R. 1952). In 1957 cultivar ´White Swirl´ (Frederick W. Cassebeer) came along with a large white flower of flat shape, which has been used very often in breeding for this characteristic flower shape. First tetraploid Siberian irises appeared around 1965 but they were unstable chimeras. First quality tetraploids were cultivars ‘Orville Fay´ and ´Fourfold White´ registered by Currier Mc Ewen in 1970.
In 1975 there were 590 cultivars of Siberian irises registered. Japanese cultivars are slightly different, sometimes called Ayame group – their stems are same length or shorter than leaves.
