Cedrus libani, the cedar of Lebanon or Lebanese cedar, 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 predominantly in Lebanon, but also in parts of Turkey, Syria, and Cyprus. Typically found at altitudes ranging from 1,000 to 2,000 meters (3,300 to 6,600 feet) above sea level in mountainous regions with rocky soils. It is the national emblem of Lebanon and is widely used as an ornamental tree in parks and gardens.
In their natural habitat or under ideal growing conditions, Lebanon Cedars can grow to heights of 30 to 40 meters (approximately 98 to 131 feet). Young trees are pyramidal, but as they age, their form becomes more horizontal or broad-spreading with level branches, often giving a tiered appearance. Trees in cultivation might not reach their full potential size due to space constraints, urban pollution, or less than ideal growing conditions.
The needles are a dark green, though they can appear almost bluish-green in certain light conditions or seasons. Each needle measures about 1 to 3 cm (approximately 0.4 to 1.2 inches). They are relatively short compared to other cedars like Cedrus deodara. The needles grow in dense clusters or whorls, often on short, spur-like shoots. This arrangement gives the foliage a bottlebrush effect from a distance.
The branches tend to be more upright or ascending, giving young Lebanon Cedars a conical or pyramid shape. As the tree ages, the branches become more horizontal or slightly drooping at the ends, creating a tiered or layered effect. Branches can grow very long, sometimes reaching several meters in length, especially in older trees.
Female cones are barrel-shaped or ovate. Initially green or purplish when young, they mature to a brown or reddish-brown color. Male cones are smaller, elongated or cylindrical and are yellowish when they release pollen. The male cones release large quantities of pollen. Each scale of the cone contains two winged seeds. Lebanon Cedars rely heavily on wind pollination.
The bark on younger Lebanon Cedars is relatively smooth and has a grayish or silvery hue. As the tree matures, the bark darkens to a deep gray or brown. It becomes deeply furrowed or fissured, with thick, rough plates or scales that give it a rugged, aged appearance. The pattern of the mature bark can resemble alligator skin or have a somewhat mosaic-like look.
This tree grows in U.S. Department of Agriculture plant hardiness zones 6 to 9. During their initial growth phase, Lebanon Cedars can grow relatively quickly, often adding about 30 to 60 cm (1 to 2 feet) in height annually under optimal conditions. This phase might last for the first 20-30 years. As the trees mature, their growth rate significantly slows. Growth in height might be just a few centimeters (inches) per year. However, the tree continues to spread, with branches extending outwards.
Lebanon Cedars are known for their longevity, with many trees living for 400 to 600 years or more. There are records of some Lebanon Cedars reaching over 1000 years old in their natural habitat, especially in areas where they have been protected or minimally disturbed. Their long life contributes to stable ecosystems, providing habitat and supporting biodiversity over centuries.
Historically, Lebanon Cedar wood was highly prized for building due to its durability, resistance to rot, and aromatic qualities. It was used in ancient constructions, notably in shipbuilding, temples, and palaces. The Temple of Solomon in Jerusalem is famously cited as being built from Lebanon Cedar wood.
In landscaping, Lebanon Cedars are planted for their majestic appearance, often as specimen trees in large estates, parks, or as avenue trees.The trees contribute to soil stabilization, especially in mountainous regions, preventing erosion and landslides. And more importantly, provide habitat for various species of birds, insects, and mammals.
Cultivation and Management
- Prefers mountainous climates with cold winters and cool summers. It thrives in well-drained, rocky soils, though it can adapt to various conditions as long as there’s good drainage to prevent root rot.
- Trees grown in regions mimicking their native mountainous climates (with cold winters and cool summers) will typically achieve larger sizes.
- Lebanon Cedars generally require minimal pruning. When pruning is necessary, it’s important to maintain the natural form. Pruning can be done to remove dead, diseased, or crossing branches, but care should be taken not to drastically alter the tree’s natural shape.
- Generally resistant, but can be affected by pests like aphids or diseases like cedar apple rust in certain conditions.
- Best planted in spring or fall. It’s crucial to ensure enough space for its mature spread, which can be significant.
- Once established, Lebanon Cedars are relatively drought-tolerant but will appreciate occasional deep watering during prolonged dry periods.
- Prune only to remove dead, diseased, or crossing branches. Young trees might need shaping to encourage a strong structure. This should be minimal to maintain the natural form.
How to Germinate Cedar of Lebanon Seeds
- Collect two or three cedar of Lebanon cones and place them in a paper bag. Wait until after the cones ripen and the scales begin to crack open. Store the paper bag in a cool, dry spot until the cones open completely and spill their seeds. Start cedar of Lebanon tree seeds in late fall, around early December.
- Soak the cedar of Lebanon seeds in a bucket of cold water for approximately three hours. Skim off and discard the seeds that float. Collect the seeds that sink.
- Wrap the cedar of Lebanon seeds in moistened cheesecloth. Place the cheesecloth in a plastic bag and store it in the refrigerator for one month. Mist the cheesecloth with water whenever it feels dry.
- Fill 3-inch square pots with a mixture of half coarse sand and half moistened peat moss. Leave the top 1 inch of each pot empty. Pour water onto the sand mixture until it trickles freely from the pot.
- Coat each cedar of Lebanon seed with a powdered fungicide specifically designed to inoculate coniferous tree seeds against damping-off. Toss the seeds in the powder and gently blow on them to remove the excess.
- Place one cedar of Lebanon seed in each pot. Cover the seeds with a loose, 3/5-inch-thick layer of the sand and peat mixture. Slowly pour water onto the sand mixture until it settles.
- Place the potted cedar of Lebanon seeds outdoors in a ventilated cold frame, under a sheltered porch or indoors in a cool room with six to eight hours of bright sunlight each day.
- Maintain constant, light moisture in the sand mixture during the germination process. Allow the surface to mostly dry out between waterings to keep the cedar of Lebanon seeds from rotting.
- Watch for germination in one to two months. Transplant the cedar of Lebanon seedlings into 1-gallon containers filled with sandy, mildly acidic potting mix in two weeks.
- Grow the cedar of Lebanon seedlings under wind-sheltered conditions with partial sun during the winter. Provide 2 inches of supplemental irrigation if there is no rain for longer than two weeks.
- Transplant the cedar of Lebanon seedlings into a very large, fast-draining bed in spring after the last frost. Provide at least 80 square feet of space for each tree.