How to Grow and Care for Greek Juniper

Among the dozens of Juniper species and hundreds of cultivars and hybrids that are popular North American landscape shrubs and trees, Greek juniper (Juniperus excelsa) occupies a unique niche. Somewhat hard to find at traditional garden retailers, Greek juniper has a reputation for being an excellent large tree for dry, rocky locations resembling its native habitat in the eastern Mediterranean basin.

Young Greek junipers take an upright growth habit with a single or multiple trunks, but as the tree matures, it gradually becomes a spreading tree with a very thick trunk, as much as six feet in diameter in very old trees. Greek juniper often takes on a very dense, rounded crown that gives the tree good shade value and makes it a home for birds seeking shelter. When young, the tree has needle-like leaves, which become scale-like as the tree matures into a massive specimen 60 feet or more in height.

This tree is normally planted as a container-grown tree or ball-and-burlap specimen in the spring or fall. It is slower-growing than most junipers, averaging roughly one foot per year.

Greek Juniper Care

Caring for a Greek juniper is much like caring for any other juniper, such as the larger cultivars of Chinese juniper (Juniperus chinensis) or common juniper (J. communis). Greek juniper will do better than other species in dry, rocky soil, and it has excellent tolerance for drought once it is well established. Given full sun and well-drained soil, this is a low-maintenance tree with a slow growth rate that won't require frequent pruning—except possibly to remove lower branches and gradually lift the canopy as the tree fulfills its destiny as a large specimen.

Light

One of the key requirements for the Greek juniper, as you would expect from a species native to the Mediterranean, is that they need lots of sunlight—a minimum of six hours daily. These trees don't grow well in shady locations.

Soil

Greek junipers tolerate a wide range of soil types provided it is well-drained. But this species will not tolerate waterlogged roots. Though native to areas with rocky, dry soil, Greek juniper will be quite at home in loamy soil and may even grow faster in more fertile conditions. Unlike other junipers (and most conifers), Greek juniper doesn't require acidic soil and does better in neutral to alkaline conditions, though it will tolerate slightly acidic soil.

Water

Once your Greek juniper is mature, it'll handle drought conditions with ease. While establishing, however, watering deeply at least once a week for the first year is recommended.

Temperature and Humidity

Green juniper is hardy in zones 5 to 9 and handles most climate conditions within that range. Young trees are more delicate and appreciate a sheltered garden position to help them establish successfully. Despite the deserved reputation as a tree for hot, dry climates, Greek juniper can also handle short bursts of winter frost down to minus five degrees Fahrenheit.

This tree is best in fairly arid climates; extreme humidity can make it susceptible to fungal diseases such as cedar rust.

Fertilizer

Though not essential, Greek junipers appreciate annual spring feeding with a balanced fertilizer, which can slightly speed up the slow growth rate. Unless rainfall is expected, it's a good idea to water thoroughly after feeding, which will allow the fertilizer to reach the entire spreading root system.

Types of Greek Juniper

There are no named cultivars of Greek juniper, but there is a notable subspecies, Juniperus excelsa subsp. polycarpos. The subspecies is virtually identical to the species plant but is native to Turkey and Iran. The subspecies has a pendula variation that has a slightly weeping growth habit.

Pruning

Because of their slow growth rate, Greek junipers don't require a lot of pruning except to remove dead or diseased branches. Where a high canopy is desired, the lower branches can be systematically cut away as the tree grows, shifting the growth habit from a shrub-like plant to a more traditional tree shape. Young plants with multiple vertical stems can be trained by eliminating competing leaders in favor of a single central stem that will become the trunk.

Pruning is best done during the winter or early spring dormant period, but not during sub-zero weather.

Propagating Greek Juniper

It's possible to propagate Greek junipers from stem cuttings, but it is not easy because these trees are very slow to develop. It can take up to a year for the cuttings to fully take root and be ready to be transplanted outdoors. Here's how to do it:

1. In early summer when the tree is actively growing, use sharp pruners to clip an eight- to 10-inch stem with plenty of needles.
2. Remove the needles from the bottom two inches of the cutting, then use a sharp knife to make one- to two-inch slits through the outer layer on each side of the stem.
3. Dip the cut end in rooting hormone, then plant it in a pot filled with standard peat-based potting mix. Thoroughly moisten the potting mix.
4. Place the pot in a large plastic bag, loosely secured. Make sure the plastic doesn't touch the cutting. Place the pot in a spot that receives bright indirect light, where the temperature is 60 to 65 degrees Fahrenheit.
5. Mist the cutting daily, and begin checking for roots after about four weeks (tug on the cutting gently; when roots have formed, you'll begin to feel resistance.
6. When the cutting has developed roots, remove the plastic and continue to grow it in a sunny location. The plant should be ready to transplant into the landscape by fall; or, it can be left in the pot to overwinter in a sheltered location and allowed to grow for another year before planting.

Vegetative propagation of Greek juniper is not always successful, so it's best to take at least three cuttings, which will increase your chances that at least one will successfully root.

How to Grow Greek Juniper From Seed

Greek juniper trees are usually monoecious, with individual trees having either female or male flowers, but not both. For this reason, the tree will not produce fertile seeds that can be propagated unless there are both male and female trees nearby where they can cross-pollinate.

If you do want to grow this tree from seed, you may need to purchase them from an online retailer. But seed propagation is not easy, as the seeds have complex stratification requirements—a few months of cold stratification, then a few months in warm conditions, and then another cold period—to germinate and sprout. Typically, the seeds are sown outdoors in the desired location and protected for a couple of years until they sprout and grow into seedlings.

Potting and Repotting Greek Juniper

Ordinarily, small juniper cultivars can make fairly good container trees, as they don't mind cramped roots and don't require much care. But Greek juniper doesn't make a very good potted tree, as it grows to be quite large and is better suited for a slightly alkaline soil rather than the acidic pH of standard potting soil. If you do try to grow a Greek juniper as a container plant, use a large, heavy, well-draining container and blend the potting mix with an amendment such as ground limestone to increase pH.

Greek juniper is a slow-growing plant, so you may be able to grow it for several years in a pot before it becomes too large. But eventually, you will have to sacrifice the tree due to its increasing size.

Overwintering

Junipers are usually quite able to tolerate winter without extra protection, but if you are growing Greek juniper near the colder end of the hardiness range (zone 5) the tree may experience some winter burn during especially cold winters. To avoid this, keep the plant well hydrated by watering it well in the fall before freezing temperatures arrive. Also, you can lay down a thick layer of mulch around the tree's base to help conserve soil moisture and regulate temperature extremes.

In colder climates, young trees may require some sheltering with a tent or wind-block made of burlap during the first few years. Such shelter will prevent winter burn.

Common Pests and Plant Diseases

Greek juniper is largely trouble-free, but it may be visited by some of the same pests and diseases that affect other juniper species.

Bagworms and mites are common pests of junipers, though neither causes fatal damage. Bagworms can be removed by hand—snipping the woven bags off and then destroying them. You can spray mites off with water, or use insecticidal soap to treat the tree.

Greek juniper may also be affected by the most common juniper disease—cedar rust. On junipers, cedar rust is usually seen as woody galls or other growths covered with gummy orange growth. Although the disease is rarely fatal, it can be disfiguring, so affected plant parts are often pruned off.