ORNAMENTAL PLANTS OF HORTICULTURE VALUE

Selection of perennials

About 250-300 species, in the Northern Temperate Zone, 100 the FSU. Only a few species are important as garden perennials, some of which are native to Russia (e.g. D. grandiflorum L.). Delphiniums are especially abundant in Central Asia and in the Caucasus, also numerous in Siberia (Altay) and the Far East.

D. laxiflorum DC.

Siberia (Altay). In meadow steppe, on slopes, on thin soils.

Flowering stem 100-150 cm, leafy. Leaves rounded heart-shaped, palmately lobed. Leaves and stem hairy. Inflorescence 20-50 cm long, sparsely branched. Flowers large, 1.6-2.5 cm long, spur 3 cm long, velvet-like, cornflower blue. V - early spring to early autumn. Fl - June-July for one month. Fr - August. P - by seed, flowering the year after sowing. Requires a sunny place on well-drained sandy loam. Z 4. New.

D. maakianum Regel

Far East (southern regions) and northeasern China. In oak forests and meadows, on slopes.

Flowering stem 50-140 cm, cylindric, bristly-pubescent. Leaves rounded, 3-lobed. Inflorescence long, sparsely branched. Flowers numerous, violet-blue, 1.5 cm long, 1.3 cm wide. V - April to August. Fl - July - August. Fr - September. P - by seed. Requires a moist loamy soil and a sunny position; however, can also grow in semi-shade. Z 5.

D. turkmenum Lipsky

Central Asia (mountains Kyurendag, Kopet-Dag). On rocky slopes.

Roots thickened. Flowering stems 30-80 cm. Basal leaves semicircular in outline, dark green, deeply 5-lobed. Stem leaves dissected, lobes narrow. Flowers few in loose racemes, butterfly-shaped, with horizontal spur, yellow. Nectaries 1.5-2.5 cm diam. V - mid spring to mid autumn. Fl - May. Fr - June, in the wild. In St. Petersburg fl - June, fr - August. P - by seed. Can grow in full sun and in semi-shade. Requires a rich moist soil. Z 6 (5). New.

D. semibarbatum Bien. ex Boiss.

Central Asia (western Tien Shan, Pamiro Alay, mountains of Turkmenia) and Iran. In meadows in the subalpine zone.

Flowering stem 30-80 (-200) cm, leaves palmatifid, inflorescence loose, about 35 cm long, flowers bright yellow, numerous. V. - mid-spring to late autumn. Fl - July. Fr - August. P - by seed, flower in 2 years after sowing. Good for group planting in sunny place but tolerant to semishade. Z 5 (4).

D. speciosum Bieb.

Caucasus (The Greater and the Lesser Ranges). In subalpine meadows and in tall-grasses communities.

Flowering stem 50-100 cm. Stem leaves rounded cordate in outline, blade two times dissected. Raceme many flowered, to 50 cm long. Flowers large 3 cm long, bright blue, widely opend, spur horizontal. V - mid-spring to mid-autumn. Fl - June, for one month. Fr - July, August. P - by seed, flower in 2 years after sowing. Prefers sunny position, tolerant to semishade. Z 5.