ORNAMENTAL PLANTS OF HORTICULTURE VALUE

Selection of perennials

Nearly 300 species confined to the Northern Hemisphere. Of 150 species of Campanula mentioned in the Flora of the USSR, 86 are endemic to the FSU. These endemic taxa are mainly concentrated in the Caucasus, especially in western locations. They also range across the mountains of Central Asia, Siberia, the Far East and the European part of Russia. Campanula plants can be found in diverse habitats: woods, meadows, among rocks frequently in the alpine and subalpine zones and occasionally in steppes and semi-deserts. All but two species are perennials, and the annuals are C. erinus L. and C. propinqua Fisch. et C. A. Mey. Some Campanula are monocarpic (C. mirabilis Albov) or biennials (C. crispa Lam., C. lyrata Lam.). They vary greatly in habit. In height they range from small alpine plants to tall subalpine plants of about 2 m. Inflorescences may be thyrsoid, racemose or capitate; some species have solitary flowers. Bellflowers are very useful in gardens of various styles, including both well-known plants and new ones. Many species are well suited to rock gardens.

C. albovii Kolak.

Caucasus (western regions). In subalpine meadows.

Rootstock underground, creeping. Leaves long-petiolate (15-20 cm), lanceolate, crenate. Flower-stalk slender, 50-70 cm, branched, with 3 to 7(9) flowers in 2 cm long, lax racemes. Flowers funnel form, dark blue or violet. V -early spring to mid autumn, although some leaves may persist through the winter. Fl - mid spring or early summer (May or June in St. Petersburg). Fr - three weeks after flowering. P - by seed. Grows well in semi-shaded sites. Z 4. New.

C. alliariifolia Willd.

Caucasus and also in Asia Minor. Among rocks in forest zone.

Taprooted plant with leafy shoots reaching 50-70 cm. Basal leaves triangular-cordate with petioles 15-20 cm. Basal stem leaves smaller, with shorter petioles, upper leaves sessile, much reduced, all with white tomentum. Flowers light violet or white, large (3-3.5 cm long) in one-sided cymose inflorescence. V - early spring to late autumn. Fl - early summer (June in St. Petersburg) for 2-3 weeks, a few flowers during July and August. Fr - a month after flowering. P - by seed or by division. Prefers sunny places. Good for group planting. Z 4.

The closely related C. dolomitica E. Busch differs in its shorter shoots and larger yellow flowers. It occurs in the Great Caucasus Range. Biology and growth reqirements are the same as for C. alliariifolia. Z 4. New.

C. aucheri A. DC.

Caucasus (central regions, Transcaucasus), Balkan Peninsula, Anatolia and northern Iran. In alpine belt on stabilized talus slopes and in rock crevices.

Mat-forming perennial with leaves crowded in rosettes, green throughout the year. Shoots loosely leafy, 10-15 cm. Flowers solitary, blue-violet, 3-4 cm long. V - starts early spring just after snow melting. Fl - mid spring (May in St. Petersburg) for 2-3 weeks. Fr - three weeks later. P - by seed, flower the year after sowing. A light sunny position and well-drained soil are required. Z 4.

Other beautiful Caucasian species related to C. aucheri, include C. anomala Fom. (stems 10-15 cm, flowers 4-5 cm long, new to cultivation); C. bellidifolia Adams (stems 10-12 cm, flowers 3-4cm long); C. biebersteiniana Roem. et Schult. (stems 10-15 cm, flowers 3-4 cm long, new to cultivation); and C. saxifraga Bieb. (stems 10 cm, flowers 3-4 cm long). All species occur in the alpine zone and are well suited to the rock garden. Z (4) 5.

C. choziatowskyi Fomin

Caucasus (Armenia). On cliffs and rocky slopes.

Clump-forming perennial with a creeping rootstock producing numerous stems. Racems pendulous, with branching reaching 30 cm, sometimes 60 cm. Flowers numerous, 1.5 cm long, deep azure blue with an especially graceful form. Corolla tubular at base with a pale blue stripe, while the calyx flares outward, so that the flower resembles a blue cup sitting in a green saucer. V - early spring to late autumn. Leaves may persist under snow protection. Fl - in early or mid-summer (June-July in St. Petersburg). Fr - 3 weeks after flowering. P - by seed. Flowers in the second year after sowing. Prefers rocky soil, does well on a dry stone wall. Z 5. New.

There are a number of other species related to C. choziatowskyi that occur in the Caucasus, barely known in cultivation. Of most interest are C. elegantissima Grossh. (stems procumbent, 10-15 cm, flowers numerous, 2-3 cm long, new to cultivation); C. kemulariae Fomin (stems procumbent, 15-25 cm, flowers 2-3 cm long); and C. ossetica Bieb. (stems arching, 20-40 cm long, flowers numerous, 2-3 cm long, new.to cultivation). All plants suitable for the rock garden and dry walls. All do well in Z 5; C. kemulariae can grow in zone 4. Both C. elegantissima and C ossetica are new reports for gardening.

C. hieracioides Kolak.

Caucasus (western region, in the gorge of the Gega River). In mountain meadows.

Rhizome short. Leafy stem slightly geniculate, 20-30 cm, mostly unbranched. Leaves sessile, ovate-lanceolate, serrate. Flowers rather large (2.5-3.5 cm), blue, clustered at top of stem. V - early spring to autumn. Fl - late spring (May in St. Petersburg) for 2-3 weeks. Fr - July. P - is relatively easy by seed. Flowers in the first year after sowing. Winters underground, cold resistant. Grows best in partial shade. Z 5 (4). New.

C. komarovii Maleev

Caucasus (northwestern regions, along the Black Sea coast between the cities of Gelendzhik and Novorossiysk). In dry meadows and on limestone slopes.

A short-lived plant, developing a rosette of leaves in the first year. Leafy stem tall (up to 50-70 cm), branched. Leaves 2-4 cm x 05.1.5 cm, pubescent. Flowers very large, up to 4-5 cm long, with bright violet-blue corolla. V - early spring to late autumn. Basal leaves persist during the winter. Fl - early summer, abundantly for three weeks with a few flowers appearing sporadically in later months. Fr - a month later. P - by seed. This wild plant can compete in its attractiveness with any garden plant due to large flowers and long blooming. Grows in full sun and dry soil. Suffers from excess moisture. Z 4.

C. mirabilis Albov

Caucasus (western region, in the valley of the Bzyb River). On rocky lime stone slopes.

Monocarpic with a thick deep tap-root. Leaves congested and numerous at the base, forming a rosette, leathery, oblong-spathulate. Flowering stem 50-70 cm, leafy, branched. Flowers the top of the main stem and along the numerous axillary branches. Flowers large, broadly campanulate, pale lilac or blue. Forms with white flowers, and yellow-margined leaves are known. Flowers in the wild after 2-3 years of vegetative growth. In cultivation in southern FSU regions it will flower the year after sowing. V - evergreen plant. In a cold climate suffers without snow protection in the winter and especially in spring from late frosts. Fl - in wild August, September, sometimes October. Can flower for two or even three months and one plant in cultivation can produce ca. 450-460 flowers. Prefers a somewhat shaded place on limestone-derived, well drained soil, suffers when exposed to direct sun light in the southern regions. P - by seed. Z 5. Probably the most beautiful of all the species of Campanula. It was called "The Queen of Abkhasian Flora" by Albov, the describer of the species.

C. sarmatica Ker-Gawl.

Caucasus (the Great Caucasus Range). In rocky and stony places and on slopes.

Taprooted plant with flowering shoots reaching 50 cm. Basal leaves oblong or ovate-oblong, petiole with blade up 10 cm long. Stem leaves densely tomentose. Flowers blue or white, nearly 3-4 cm wide, in loose unilateral raceme. V - early spring to late autumn. Fl - late spring (end of May in St. Petersburg) for 2-3 weeks or longer. Fr - July. P - by seed. Flowers the year after sowing. Prefers a sunny position, well-drained soil. Z 4.

This species is closely related to C. collina Sims, well-known in cultivation, and similar to it in habit (not to C. alliariifolia, as stated in some reference books).

Among closely related species, two are of special interest: C. annae Kolak., with large flowers to 4-5 cm long and C. schistosa Kolak., stems 20-30 cm, flowers 4-5 cm long. Z 5 (4). Both new.

C. turczaninovii Fed.

Siberian mountains and northern Mongolia. Tundra zone and coniferous forests.

Taproot rather long, leaves clustered in a rosette. The flowering stem 20-30 cm, seldom more. Leaves oblong-lanceolate, 5-15 cm long. Flowers 2-5, up to 4 cm long, located at top of stem. Corolla narrowly funnel-shaped, deep blue. V - early spring to late autumn. Fl - early summer (June in St. Petersburg) for 2-3 weeks. Fr - July. P - by seed. Flowers the second year after sowing. Can grow in a semi-shaded position. Z 4. New.

Among mat-forming plants, C. alpigena C. Koch, C. andina Rupr., C. armazica Charadze, C. chamissonis Fed., C. ciliata Steven, C. fominii Grossh., C. kryophila Rupr., C. lasiocarpa Cham., C. radchensis Charadze, C. sosnowskyi Charadze and C. tridentata Schreb. should also be mentioned. All new except for C. chamissonis, C. lasiocarpa, and C. tridentata. They are native to the Caucasus or the Far East. All are very good for the rock garden. Among tall-growing species (about 100 cm or more) C. letschumensis Kem.-Nath., new and C. makaschvilii E. Busch, both native to the Caucasus, are of gardening value. Good for group planting. Z 5.