Siberian juniper

Synonyms: Juniperus alpina (Suter) Gray, Juniperus communis ssp. alpina (Suter) Celak., Juniperus communis ssp. nana (Willd.) Syme, Juniperus communis var. alpina Suter, Juniperus nana Willd., Juniperus communis var. montana Aiton, Juniperus communis var. saxatilis Pall.

Siberian juniper (Juniperus sibirica Burgsd.) – a species of plants of the genus Juniperus of the family Cupressaceae. Some botanists consider this species a variety of common juniper - Juniperus communis var. saxatilis. The species was first described in 1787 by the German forester Friedrich August Ludwig von Burgsdorf in his work «Anleitung zur sicheren Erziehung Holzarten». In cultivation since 1879.

In nature it grows in mountainous regions - Heilongjiang, Jilin, Liaoning, Inner Mongolia, Xinjiang, Tibet Autonomous Region [Korea, Japan, Mongolia, Russia (Far East, Siberia); in the Himalayas, in Central and East Asia, in Eastern Europe, in the east of North America. In Ukraine it is found in Crimea. It grows in highlands, on rocks, rocky slopes or screes, barren meadows, in sparse deciduous woodland and in thickets of dwarf cedar or birch (Middendorff's birch). It ascends to elevations of 600-4200 m above sea level.

It is a monoecious or dioecious coniferous evergreen plant. A low shrub up to 1 m high with a prostrate or spreading crown. Very hardy. Grows slowly, up to 0.5 cm per year, reaching 0.5 m in height in 10-15 years. Densely branched, less often with erect, three-sided short and thick branches. Young shoots are covered with light-brown glossy smooth bark, branches – gray-brown. Internodes shortened, 1-4 mm long. Root system deep, extending up to 2 m deep.

Leaves needle-like, arranged whorled in threes along the shoot, appressed to the branches, 4-8 (10) mm long, densely sessile, closely set, sabre-shaped curved, spiny, with an awl-shaped tip. On the upper side of the needles there is a groove with a bluish-white stomatal band, on the lower side green, convex, with a blunt keel. Leaves are retained for 2 years. Does not brown in winter.

Male cones are terminal, sessile, 2-3 times shorter than the leaves. Berry-cones 6-8 mm in diameter, globose, slightly fleshy, borne on short stalks, black with a glaucous bloom with 2-3 seeds inside, ripen in the second year. Seeds oval, 2-3-angled, with a blunt short beak, reticulate-wrinkled on the back, brownish. Fruiting in June-August.

Chromosome number: 2n = 22

Forms: "Viridis" ('Viridis'), "Glauca" ('Glauca'), "Compacta" ('Compacta')

Hardiness: 4-9 (-29°C)

Site: undemanding to soil, can grow on rocky substrate with a small amount of fine earth or on peat soil. Prefers moderately moist substrate. Likes sunny positions but tolerates light shade. Not salt-tolerant. Drought-tolerant.

Planting: recommended spacing between plants 0.5 or 1.2-2 m. Planting depth – 70 cm. Drainage as needed: crushed brick or sand, layer 15-20 cm. Soil mix: sod soil, peat and sand in ratio 1:2:1. Does not like transplanting; preservation of the root ball and abundant watering are necessary.

Care: in spring (April-May) apply nitroammophoska 30 - 40 g/m2. In a dry summer it is recommended to water the plant 2-3 times per season and to spray in the evening once a week. Mulch with peat or sawdust in a layer of 5-8 cm.

Pruning: tolerates heavy pruning and clipping well, retains shape for a long time.

Diseases: rust (Arcerid (50 g per 10 l of water) spray 4 times at 10-day intervals), Schütte, biatorrellal and Nectria canker, alternaria, pear rust fungus.

Pests: aphids (Fitoverm (2 g per 1 l of water) spray 2 times at 10-14 day intervals), leaf-mining moth (Decis (2.5 g per 10 l) spray 2 times at 10-14 day intervals), spider mite (Karate (50 g per 10 l)), scale insects (carbophos (70 g per 10 l of water)), galls, sawfly, shoot moth, pine looper.

Propagation: propagated by seeds and cuttings. Rooting of cuttings up to 80%.

Uses: Little known in cultivation. Very ornamental due to its dense two-colored foliage. Recommended for rock or alpine gardens, landscaping and slope stabilization, ornamenting plots, in heather gardens.