ORNAMENTAL PLANTS OF HORTICULTURE VALUE

Selection of perennials

About 20-40 species, depending on classification, in the Northern Temperate Zone. 25 species in the FSU according to Russian authorities, mainly in Siberia, also in the Caucasus, the Far East and the European parts of the country. Among species well-known in horticulture are T. asiaticus L. with bright yellow flowers and T. europaeus L. with lemon-yellow flowers. Some are unknown or poorly known in cultivation.

T. altaicus C. A. Mey.

Siberia (Altay), Central Asia (Dzungarskiy Alatau, Tarbagatay, Pamiro Alay, Tien Shan), northwestern China and western Mongolia. In mountain upper forests and meadows in the alpine zones, at 900-2,000 m.

Plant 20-75 cm. Roots tufted. Basal leaves long-petiolate 5-7 partipalmate, lobes incised, serrate. Stem leaves sessile, smaller. Flowers large, 4-5 cm diam., golden yellow or orange with dark centre (because of dark purple stigmas). V - early spring to early autumn, in St. Petersburg April-September. Fl - May. Fr - July. P - by division and by seed. In partial shade and in full sun. Z 3 (2). New.

T. dschungaricus Regel is closely related

Central Asia (Dzungaro-Tarbagatay, Pamiro Aly, Tien Shan) and northwestern China.

In forests and alpine meadows up to 4,000 m. Basal leaves reniform, palmately 5-partite. Flowers up to 6-7 cm diam., golden yellow. Very similar to T. altaicus.

T. macropetalus (Regel) F. Schmidt (T. chinensis Bunge)

Far East (southern and western regions, Sakhalin), China and Japan. Wet meadows, shrub thickets, open places, forest margins.

Plant 30-60 cm. Roots tufted. Basal leaves long-petioled, palmately 3-5 partites, 5-20 cm x 3-10 cm. Stem leaves smaller, upper sessile. Flowers large, 5-6 cm diam., orange-yellow. Petal nectaries twice as long as sepals. V - early spring to early autumn, in St. Petersburg April-September. Fl - a month later than the other species, in St. Petersburg July. P - mainly by division, also by seed. Undemanding as to soil, tolerates shade, prefers partial shade. Z 4 (3).