The cedar of Lebanon tree (Cedrus libani) is an evergreen with beautiful wood that has been used for high quality timber for thousands of years. Lebanon cedar trees usually have only one trunk with many branches that grow out horizontally, spiraling up. They are long-lived and have a maximum life span of over 1,000 years. If you are interested in growing cedar of Lebanon trees, read on for information about these cedars and tips about cedar of Lebanon care.
I. Appearance and Characteristics
Cedrus libani, the cedar of Lebanon or Lebanese cedar (Arabic: أرز لبناني, romanized: ʾarz Lubnāniyy), is a species of tree in the genus Cedrus, a part of the pine family, native to the mountains of the Eastern Mediterranean basin. It is a large evergreen conifer that has great religious and historical significance in the cultures of the Middle East, and is referenced many times in the literature of ancient civilisations. It is the national emblem of Lebanon and is widely used as an ornamental tree in parks and gardens.
Cedrus libani can reach 40 m (130 ft) in height, with a massive monopodial columnar trunk up to 2.5 m (8 ft 2 in) in diameter. The trunks of old trees ordinarily fork into several large, erect branches. The rough and scaly bark is dark grey to blackish brown, and is run through by deep, horizontal fissures that peel in small chips. The first-order branches are ascending in young trees; they grow to a massive size and take on a horizontal, wide-spreading disposition. Second-order branches are dense and grow in a horizontal plane. The crown is conical when young, becoming broadly tabular with age with fairly level branches; trees growing in dense forests maintain more pyramidal shapes.
Shoots and leaves
The shoots are dimorphic, with both long and short shoots. New shoots are pale brown, older shoots turn grey, grooved and scaly. C. libani has slightly resinous ovoid vegetative buds measuring 2 to 3 mm (0.079 to 0.118 in) long and 1.5 to 2 mm (0.059 to 0.079 in) wide enclosed by pale brown deciduous scales. The leaves are needle-like, arranged in spirals and concentrated at the proximal end of the long shoots, and in clusters of 15–35 on the short shoots; they are 5 to 35 mm (0.20 to 1.38 in) long and 1 to 1.5 mm (0.039 to 0.059 in) wide, rhombic in cross-section, and vary from light green to glaucous green with stomatal bands on all four sides.
Cones
Cedrus libani produces cones beginning at around the age of 40. Its cones are borne in autumn, the male cones appear in early September and the female ones in late September. Male cones occur at the ends of the short shoots; they are solitary and erect about 4 to 5 cm (1.6 to 2.0 in) long and mature from a pale green to a pale brown color. The female seed cones also grow at the terminal ends of short shoots. The young seed cones are resinous, sessile, and pale green; they require 17 to 18 months after pollination to mature. The mature, woody cones are 8 to 12 cm (3.1 to 4.7 in) long and 3 to 6 cm (1.2 to 2.4 in) wide; they are scaly, resinous, ovoid or barrel-shaped, and gray-brown in color. Mature cones open from top to bottom, they disintegrate and lose their seed scales, releasing the seeds until only the cone rachis remains attached to the branches.
The seed scales are thin, broad, and coriaceous, measuring 3.5 to 4 cm (1.4 to 1.6 in) long and 3 to 3.5 cm (1.2 to 1.4 in) wide. The seeds are ovoid, 10 to 14 mm (0.39 to 0.55 in) long and 4 to 6 mm (0.16 to 0.24 in) wide, attached to a light brown wedge-shaped wing that is 20 to 30 mm (0.79 to 1.18 in) long and 15 to 18 mm (0.59 to 0.71 in) wide. C. libani grows rapidly until the age of 45 to 50 years; growth becomes extremely slow after the age of 70.
II. How to Grow and Care
Sunlight
Plant your cedar of Lebanon tree in a spot with at least eight to 10 hours of sunlight daily. This shouldn’t be too hard to achieve—chances are, the tree will be the tallest thing in your landscape (at least, after a few years’ time), so it’s unlikely that it will be shaded by other trees and kept out of the sun.
Temperature and Humidity
The cedar of Lebanon tree is a very adaptable varietal and can handle a range of temperatures, both cold and warm. It can thrive in the high heat of summer (similar to the conditions in its native land), and withstand very low temperatures in winter.
Watering
A newly-planted tree should be watered regularly. Water every week or so, keeping the soil moist but not soggy. Once established, cedar of lebanon is fairly drought tolerant, but in extremely hot and dry weather you should still water occasionally.
Soil
Cedar of Lebanon trees prefer acidic soil, but can also be grown in soil with neutral and alkaline pH levels. When it comes to the composition of their soil, they will do best if planted in moist but well-drained soil. Any soil that is too mucky or poor draining will result in root rot and ultimate failure.
Fertilizing
Cedar of lebanon doesn’t need a lot of fertilizer, but a small amount can help encourage growth. Every other year, fertilize your cedar of lebanon with a well-balanced fertilizer, like a 10-10-10 (N-P-K). It’s best to fertilize in the spring or early summer when the tree is putting on new growth.
Pruning
If you have the space to let your cedar of lebanon grow, there’s no need to prune. However, the tree can be pruned in early spring before it begins putting on new growth. You can prune to shape it or to prevent it from growing too close to structures or other trees. You can also prune dead or damaged limbs.
When pruning, always sanitize your pruning saw in between trees. This can help prevent the spread of fungal diseases and bacteria from tree to tree.
Propagation
Cuttings of Lebanese cedar are virtually impossible to root. The only method of propagation is from seed.
From seed
To grow the tree from seed takes patience but it can be done.
- Collect several cones from an established tree. Place the cones in a paper bag and store them in a cool, dry place until the cones “ripen,” as indicated by the scales cracking open and spilling their seeds.
- Soak the seeds in a bucket of water for three hours or more. Discard any seeds that float (they’re not viable) and collect any that sink.
- Wrap the viable seeds in moistened cheesecloth or paper towel and place them in a plastic bag. Store in the refrigerator for one month while the seeds germinate, misting the cloth whenever it feels dry to the touch.
- Plant in pots that are at least 3 inches deep with potting soil. Coat each seed with fungicide, place in an individual pot, and top with sand and peat. Water until the mixture settles and drains from the holes at the base of the pot.
- Place pots in a sunny spot. Once seeds germinate, move seedlings to larger containers. Grow them all winter and plant in spring after the last frost.
Potting and Repotting
Due to its size, Lebanese cedar is not suitable to be grown in pots but a dwarf variety can be trained as a bonsai.
Overwintering
The tree is hardy to USDA zone 5 and needs no winter protection. The roots of a potted bonsai, however, might need to be insulated against winter cold by wrapping the container in burlap and bubble wrap, or placed in an insulating silo for overwintering.
Pests and Diseases
Common Pests & Plant Diseases
There are not too many problems associated with cedar of Lebanon trees. You may have an aphid attack from time to time.3 This can be naturally managed by ladybugs or removed simply by spraying them off the branch with water.
Root rot is another issue but can be rectified by maintaining well-draining soil.1
Common Problems with Lebanese Cedar
Browning Needles
Although it’s expected that the tree will drop some needles in the spring and fall to make room for new growth, browning needles in the summertime may be a cause for concern. This could be a sign of a weevil or spider mite problem. Treat with insecticidal soap and spray a protectant oil in the spring to prevent summertime infestations.
Maintenance
III. Uses and Benefits
Cedar wood is prized for its fine grain, attractive yellow color, and fragrance. It is exceptionally durable and immune to insect ravages. Wood from C. libani has a density of 560 kg/m3; it is used for furniture, construction, and handicrafts. In Turkey, shelterwood cutting and clearcutting techniques are used to harvest timber and promote uniform forest regeneration. Cedar resin (cedria) and cedar essential oil (cedrum) are prized extracts from the timber and cones of the cedar tree.