ORNAMENTAL PLANTS OF HORTICULTURE VALUE
Selection of perennials
About 200-250 species in the temperate regions of the Northern
Hemisphere. In the FSU about 60-70 species, depending on
classification. They occur in various regions but mainly in the
Caucasus, Central Asia, the Altay, also in the Transbaikal area
and the Far East. Some of the Russian species are well-known
garden plants, some have been involved in hybridization. The
native irises are of great interest today. Plants increase the
number of their flowers under cultivation.
I. albertii Regel
Central Asia (Tien Shan). In foothills, on grassy and stony
Rhizomatous plant 40-50 cm. Leaves as tall as stem, sword-shaped,
glaucous green, 2.5-3.0 cm broad. Flowers purple-violet, terminal,
1-3 on the main and lateral shoots. V - mid-spring to late autumn,
in St. Petersburg May-October. Fl - May for 2-3 (4) weeks. Fr -
August. P - by division and by seed. Does well in sunny and
semi-shaded positions. Z 4.
The closely related species
I. imbricata Lindl. (I. sulphurea C. Koch) occurs
in the southern and eastern Transcaucasus, northern Iran and northern
Anatolia. Flowers sulphureus yellow, and leaves broader than in I.
albertii. Prefers semi-shaded places.
I. bloudowii Ledeb.
Siberia (southern regions), Central Asia (Dzungaro-Tarbagatay),
Far East (Ussuriskiy Kray), northern China and Mongolia. Meadows,
valleys, forest margins, along streams in the alpine zone.
Rhizome thick, branched. Plant to 20-30 cm. Leaves falcate,
3-5, in rosette, as tall as stem. Flowering stem bears 2-4 leaves
and 2 flowers. Flowers large, brown-yellow with violet veins. V -
from early spring to late autumn. Fl - May. Fr - June. P - by
division and by seed. Requires a semi-shaded site and moist but
well-drained soil during the vegetative period. Very well suited
to the rock garden, and for group planting. Z 4.
I. darwasica Regel
(Central Asia: Pamiro-Alay) differs in yellow flowers.
Grows in sunny dry places. Z 5,6.
I. ensata Thunb. (I. kaempferi Sieb. ex Lem.)
Siberia (southern regions), Far East, northeastern China, Korea
and Japan. Moist meadow slopes, fluvial plains with rich lime-free
Rhizomatous plant 60-90 cm. Leaves sword-shaped, with prominent
midrib, 1.0-1.5 cm broad. Stem shorter than leaves. Flowers 2-4,
large, dark purple or violet, terminal. V - May to October. Fl -
June-July. Fr - September. P - by seed and division. Known from
Japan as an ancestor of the numerous cultivars of Japanese irises.
Z 5 (4).
I. korolkowii Regel
Central Asia (Tien Shan, Pamiro Alay), NE Afghanistan. On dry
Rhizomateus plant with thin stolons 30-60 cm in height. Leaves
grey green linear-sword, shorter than flowering stem. Flowers 2-3
per stem, large (7 x 10 cm), white with brown-purple veins. V -
early spring. F - May-June. Fr. - August. P - by rhizome division
and by seed. Requires dry soil and sunny position. Z 5.
I. lactea Pall. (I. ensata auct., non
Thunb., I. biglumis Vahl).
Siberia (southern regions), Kazakstan, eastern Mongolia,
northwestern China and Afghanistan. Steppe meadows, turf
Rhizomatous plant 20-50 cm. Leaves linear, glaucous green,
20-40 cm x 0.5-2.0 cm. Flowers light blue, 4-6 cm diam. V -
mid-spring to late summer. Fl - June for 2-3 weeks. Fr - August.
Propagation by seed and division. Prefers sunny places, but can
grow successfully in shady places. Cultivated since the XVI
century, used in hybridization for selection of dwarf bearded
irises. Suitable rock gardens and group planting. Z 5 (4).
I. laevigata Fisch.
Siberia (eastern regions), Far East (Sakhalin, Kamchatka, Kuril
Islands), Korea, Mongolia and Japan. Meadows, swamps, lake shores,
Rhizomatous plant 60-90 cm. Leaves 75-90 cm x 4 cm, surpassing
the stem. Flowers blue, 3-4 at the top of the main shoot and also
2-3 flowers on a lateral shoot. V - mid spring to mid autumn, in
St. Petersburg May-October. Fl - June for 2-3 weeks. Fr - August.
P - by seed and division. Shade tolerant. Z 4.
I. pumila L.
European parts of the FSU (southern regions), Caucasus (eastern
regions), central and southern Europe. Stony slopes, steppes, on
gravelly soil, solonchaks.
Rhizomatous plant 10-15 cm. Leaves glaucous green, broadly
linear, 10-15 cm x 1.0-2.0 cm. Flowers solitary, 5-7 cm diam, of
various colours (yellow to lilac). V - mid-spring to late autumn
(leaves can overwinter). Fl - late spring-early summer, in St.
Petersburg May- June. Fr - August. P - by seed and division.
Requires a sunny place, however can grow in a shady position.
Cultivated since the XVI century and was used for selection of
dwarf bearded irises. Z 5 (4).
I. ruthenica Ker-Gawl.
Siberia (southern regions), Central Asia (Tien Shan), northern
Mongolia and northern China. Meadows, forest margins, grassy and
Rhizomatous plant 20-30 cm. Leaves linear-lanceolate, somewhat
arch-like, curved-decumbent, 40 cm x 0.4-0.6 cm. Flowers blue-violet,
solitary on short peduncles (10-20 cm). V - mid spring to mid autumn,
in St. Petersburg April-October. Fl -May-June for 2-3 weeks. Fr -
August. P - by seed and division. For group planting and the rock
garden. Does well in sunny places and in semishaded places. Z 4.
I. ruthenica is close to I. uniflora Pall.
ex Link growing in Siberia (Transbaykal area), the Far East (Amur
River basin, Primorskiy region) and northeastern Mongolia. On steppe
and stony slopes. I. uniflora differs in the shorter, thick,
coriaceous, reddish leaves. Z 4. New.
I. setosa Pall.
Siberia (eastern regions), Far East (Primorie, Kuril Islands),
northeastern China and Japan. Forest margins, birch woods, dry and
wet meadows, peat bogs.
Rhizomatous plant 50-100 cm. Leaves sword-like, slightly glaucous,
50 cm x 2,5 cm. Upper stem leaves smaller than basal ones. Flowers
blue-purple, nearly 6-7 cm long, solitary or 2-3 in a raceme. V -
April-October. Fl - in June-July for 2-3 weeks. Fr - August-September.
Frost-resistant, tolerates shade. Propagation by seed and division.
Z 4 (3).
I. sibirica L.
European part of the FSU, Caucasus, western Siberia, Sayans and
central Europe. In clearings and forest margins and in meadows.
Rhizomatous plant 70-100 cm. Leaves linear, 50-80 cm x 4 mm.
Flowering shoot with 2-3 flowers on short pedicels bears 3 small
leaves. Flowers violet or white, 5-7 cm diam. V - mid spring to
late autumn, in St. Petersburg April-October. Fl - June for 2-3
weeks. Fr - August. Shade-tolerant.
A closely related species is I. sanguinea Donn,
occurring in Siberia, the Primorskiy region of the Far East,
Mongolia, Japan and northeastern China. It differs in its more
coriaceous leaves and broad perianth lobes.
There are some species belonging to subsection Oncocyclus
(Siemss.) Benth. which are extremely attractive, however, very
difficult in cultivation. They did not grow in St. Petersburg
because of its climate (excess moisture in summer, too cold in
winter). Many of them occur in the Caucasus and also in Central
Asia. I. acutiloba C.A Mey., western Transcaucasus,
flowers 6-8 cm, grey-purple-violet. I. camillae
Grossh., western Transcaucasus, flowers 6-9 cm, white-blue-brown.
I. ewbankiana Foster, mountains of Turkmenia and
northern Iran, flowers 6-9 cm, of various colours. I.
grossheimii Woronow ex Grossh., southern Transcaucasus,
flowers 5-8 cm, pale grey-dark brown. I. helena
C. Koch (C. Koch), eastern Transcaucasus, northern Turkey and
northern Iran, flowers 6-7 cm, grey brown or grey yellow.
I. iberica Hoffm., central Transcaucasus, flowers
8-10 (-12) cm, white yellow-dark brown. I. lycotis
Woronow, southern Transcaucasus, flowers 6-10 (18) cm, purlpe
violet with blck spot. I. paradoxa Steven, southern
and eastern Transcaucasus, flowers 5-8 (12) cm, pale violet-velvet
black. I. schelkownikowii (Fomin) Fomin, southern
and eastern Transcaucasus, flowers 8-10 cm, grey purple violet.
These species produce many hybrids in the wild. They are especially
abundant in two regions of the Transcaucasus: Nakhishevan and