Sitka spruce

Synonyms: Sitka spruce

Sitka spruce – a species of evergreen trees of the genus Spruce of the family Pinaceae. In nature it grows in the western part of North America from Amsin (Alaska) to northern California. In the mountains it rises to 900-1000 m above sea level. Grows along rivers and on seaward-facing mountain slopes. Occurs in pure and mixed stands with Douglas-fir, western hemlock, grand fir, red alder, noble fir, bigleaf maple, sequoia. In cultivation since 1831. Was discovered by Archibald Menzies in 1792. Lives 500-800 years.

It is a tall tree 45-60 (90) m in height (in cultivation up to 40 m), with a trunk diameter of 120-240 (480) cm. Annual growth up to 10-15 years reaches 10 cm, in more mature age – 30 cm. Crown dense, broadly pyramidal. Bark thin, gray or reddish-brown, fissured, scaly. Buds conical, 4-5 mm long and 2-3 mm wide, resinous. Young shoots light brown, glabrous, less often slightly pubescent.

Needles 15-18 (25) mm long and 1 mm wide, flattened, with 6-8 stomatal lines on the underside on each side of the keel, stiff, prickly, slightly keeled; the upper surface of the needles is green, the underside silvery, which gives the crown a bluish-steel tint.

Cones cylindrical in shape, on short stalks, 5-10 cm long, 2.5-3 cm wide, yellow-green, turning light brown at maturity. Scales thin, emarginate-toothed. Ripen in September-October. Seeds light brown, 2-3.5 mm long. Wing light yellow, 4-5 times larger than the seed.

Ornamental forms: 'Glauca', 'Siberzwerg', 'Renken', 'Tenas', 'Papoose'.

Site: In cultivation it is undemanding to soil. Shade-tolerant, but grows well in sunny locations. Demanding of air humidity. Can grow on temporarily flooded areas. Smoke- and gas-resistant.

Planting: Soil mix: turf and leaf soil, peat, sand in the ratio 2:2:1:1. Drainage is made of broken brick, layer 15-20 cm. Planting depth: 50-70 cm. The root collar at ground level. Recommended spacing between plants – 2-3 m.

Care: after planting you can apply 100-150 g of nitroammophoska. During dry periods it is recommended to water daily 10-12 L per plant. It is also desirable to irrigate the crown. Loosening is carried out to a depth of 5-6 cm, while peat is not removed but mixed with the soil. Young seedlings need protection with fir branches for the winter. In youth it needs protection from spring sun; for this you can throw non-woven fabric in 2 layers over the tree or place special protective shields on the south side.

Pruning: tolerates pruning well. With proper formation of a hedge, an effect of an “impassable green wall” can be achieved. It is recommended to pinch dominant and shorten lateral shoots during growth.

Diseases: Schütte, snow Schütte, fusariosis, stem and root rot, bark necrosis, canker (wound) cancer, cone rust, spruce tip borer.

Propagation: by seed, cuttings, grafting or layering.

Uses: is a national resource of the USA. Widely used in carpentry, pulp and paper and furniture production, as the wood has a beautiful brownish shade. In landscape construction it is used similarly to Norway spruce. Ornamental due to its attractive branching bluish crown and numerous light-brown cones.