Oriental spruce can reach a height of 50 to 60 feet with a spread of 15 to 25 feet. The delicate texture of the small needles and graceful habit make this a good choice for the home landscape.
I. Appearance and Characteristics
Picea orientalis, commonly known as the Oriental spruce or Caucasian spruce, is a species of spruce native to the Caucasus and adjacent northeast Turkey.
It is a large coniferous evergreen tree growing to 30–45 m tall or 98–145 feet (exceptionally to 57 m), and with a trunk diameter of up to 1.5 m (exceptionally up to 4 m). The Caucasian Spruce can also be found in Northern Iran, though its numbers have decreased due to deforestation.
The shoots are buff-brown and moderately pubescent (hairy). The leaves are needle-like, the shortest of any spruce, 6–8 mm long, rhombic in cross-section, dark green with inconspicuous stomatal lines. The cones are slender cylindrical-conic, 5–9 cm long and 1.5 cm broad, red to purple when young, maturing dark brown 5–7 months after pollination, and have stiff, smoothly rounded scales.
II. How to Grow and Care
Oriental spruce requires well-drained soil and thrives in full sun or partial shade, making it adaptable to different garden spaces. Special care points include maintaining consistent soil moisture without waterlogging and offering protection from wind. Pruning should be minimal, focusing only on the removal of dead or damaged branches to maintain its natural conical shape.
Sunlight
Oriental spruce is shade-tolerant, so it doesn’t need much direct sunlight to grow. From spring through early summer, it’s best to expose the tree to light for a duration of over 6 hours a day, but a lack of light for a short time won’t affect its growth. In summer, when sunlight is harsh, it’s best to shade small trees grown outdoors to protect them from long-term, blazing light. If they are potted indoors, move them to a cool, shaded place.
Temperature
Oriental spruce likes cool and moist climates. The ideal temperature range for tree growth is 4 to 18 ℃. It’s hardy and tolerant of temperatures as low as -30 ℃, but young trees and tender branches are less cold-resistant.
Oriental spruce likes moisture, it has good adaptability and is slightly drought-enduring. During the spring and summer growing seasons, the tree prefers higher air humidity (70-80%), while in the fall and winter, lower air humidity (55-65%) can help it grow more sturdy.
Watering
Originating from the mountainous regions, oriental spruce is accustomed to moderate moisture levels and can withstand short periods of dryness. It thrives in a balance of consistent moisture without being waterlogged, showing a preference for slightly humid conditions. Watering should be adjusted to once every 1-2 weeks, ensuring that the soil has dried out partially between watering sessions. As an evergreen plant, oriental spruce maintains its foliage year-round, requiring careful attention to watering during the growing season to support its continuous growth.
Soil
Oriental spruce grows well in fertile, deep, well-drained, slightly acidic soils. The best soil pH range is 5.1-7.3, making both sandy soil or slightly clay-like soil good choices. As the tree grows slowly and has a long life span, the soil layer should be about 70 cm thick. If barren, the soil can be improved by adding nutrient soil or organic manure.
Fertilizing
For optimal growth, fertilize oriental spruce with balanced nutrition fertilizers in early spring. Apply at 3-month intervals during growing season, adhering to label-specified dosages. Fertilizing enhances oriental spruce’s vigor, health, and aesthetic appeal. Seasonally adjust amounts; less in autumn to prepare for dormancy. Use slow-release formulations to prevent over-fertilization. Water soil before and after applying fertilizer to prevent root burn. Experienced gardeners may custom-tailor amendments based on soil tests. Always wear gloves and wash hands post-application.
Planting Instructions
To grow oriental spruce in a yard, purchase seedlings and transplant them in early spring. Get the planting pit ready one week before transplanting; its diameter needs to be about 20 cm longer than that of the root ball and have a depth of about 15 cm deeper. It should be no less than 6 m away from other plants. Add organic fertilizers to the bottom of the planting pit before transplanting and mix them well with the soil.
Place the seedling vertically into the pit, shovel 2/3 of the soil back, and water thoroughly once to make sure the moisture around the plant’s roots is sufficient. Then, fill the pit fully up with soil and water again. Stomp the soil firmly and keep the pit surface level with the ground. If it’s often windy at the planting site, support the young tree with wood sticks or metal poles in case a strong gale threatens to tilt it or knock it down.
Indoor potted oriental spruce can be directly purchased. The tree grows slowly and usually doesn’t require repotting. Repotting is only necessary if the needles turn yellow and fall off the tree, the roots around the pot brim or at the bottom wither and dry up, or the soil in the pot compacts. Move the majority of the original soil to the new pot with the plant, and add small amounts of organic fertilizers and new soil to provide more nutrients for its growth.
Pruning
Oriental spruce has lush terminal buds. The tree usually takes on a beautiful triangular shape and does not require pruning in general. When overly pruned, its incisions secrete rosin excessively which affects the tree’s normal growth. It’s best to trim off overly dense, diseased, and dried branches during the plant’s winter dormancy. Prune and beautify the treetop in early spring when buds sprout. About 1/2 of the young branches can be pruned off to create your desired shape. For large, mature trees, it’s a good idea to prune off all the branches on the lower trunk to reduce nutrition consumption.
When growing oriental spruce for Christmas decorations, you need to control height and width. Prune the treetop and lateral branches appropriately short and continue to cut the newly-grown buds short, as well. Repeat this process many times. Seal pruning incisions with wax or duct tape to keep rosin from effusing.
Propagation
An exquisite conifer, oriental spruce can be propagated effectively through sowing. For best results, use fresh seeds that are sown into well-drained soil mixtures, ensuring they are kept moist and at a cool temperature to facilitate germination. Patience is key, as oriental spruce seeds may take some time to sprout. Once established, the young plants will thrive in a variety of settings, appreciating sun to partial shade and regular watering schedules to mimic their natural, forested habitats.
Transplanting
For best success, transplant oriental spruce when the rebirth of nature begins in early to mid-spring, ensuring a mild start and root establishment. Choose a spot with good drainage and some shelter. A friendly word of advice: ensure ample space for mature growth.
III. Uses and Benefits
It is a popular ornamental tree in large gardens, valued in northern Europe and the USA for its attractive foliage and ability to grow on a wide range of soils. It is also grown to a small extent in forestry for Christmas trees, timber and paper production, though its slower growth compared to Norway spruce reduces its importance outside of its native range. P. orientalis and the cultivars ‘Aurea’ and ‘Skylands’ have gained the Royal Horticultural Society’s Award of Garden Merit.
