Although the original species (Juniperus chinensis) is a medium to large tree, you won’t find these trees in garden centers and nurseries. Instead, you’ll find Chinese juniper shrubs and small trees which are cultivars of the original species. Plant taller varieties as screens and hedges and use them in shrub borders. Low-growing varieties serve as foundation plants and groundcovers, and they work well in perennial borders.
I. Appearance and Characteristics
Juniperus chinensis, the Chinese juniper (圆柏, 桧) is a species of plant in the cypress family Cupressaceae, native to China, Myanmar, Japan, Korea and the Russian Far East. Growing 1–20 metres (3+1⁄2–65+1⁄2 feet) tall, it is a very variable coniferous evergreen tree or shrub.
The Juniperus chinensis is one of the top species used in the Japanese art of bonsai, referred to as “Shimpaku.” Among the multiple cultivars of Shimpaku found in Japan, the most desirable due to its tight, fine foliage and excellent growing habits, is the “Itoigawa” variety.
The leaves grow in two forms, juvenile needle-like leaves 5–10 millimetres (1⁄4–3⁄8 inch) long, and adult scale-leaves 1.5–3 mm long. Mature trees usually continue to bear some juvenile foliage as well as adults, particularly on shaded shoots low in the crown. This species is often dioecious (either male or female plants), but some individual plants produce both sexes of flowers. The blue-black berry-like cones grow to 7–12 mm in diameter, have a whitish waxy bloom, and contain 2–4 seeds; they mature in about 18 months. The male cones, 2–4 mm long, shed their pollen in early spring.
II. How to Grow and Care
Sunlight
Chinese juniper needs sufficient sunlight and can only grow normally with more than 4 hours of sunlight per day. If it’s planted under big trees or in any other shady environment, its growth slows, with sparse branches and yellowing leaves. It needs to be shaded on hot summer days to avoid sunburn.
Temperature
Chinese juniper is mainly distributed throughout the Northern temperate zone. It likes cool weather, but can also tolerate heat. Some species blossom multiple times a year in warm areas. It doesn’t require much air humidity and is somewhat drought-tolerant.
Watering
Right after planting, water once every other day, as ample water helps it adapt to the new environment. A week later, the watering frequency can be reduced, because chinese juniper is a drought-tolerant plant that may grow poorly in excessive water. In hot summers, it can be watered more to avoid dehydration.
Soil
Chinese juniper can grow in all types of soils and has no requirements for soil pH. But it grows most robustly in loose, fertile soils with good water drainage. It has strong roots and can survive in dry, sandy lands and rock cracks, but cannot tolerate standing water.
Fertilizing
Chinese juniper grows very slowly and doesn’t require much fertilizer. Too much can result in spindly branches and leaves ruining the plant’s good looks. To make the plant lush, healthy, and robust, use base fertilizer at planting. Add diluted organic fertilizer 2-3 times every spring, and 1-2 times every fall.
Planting Instructions
To transplant, dig a planting pit with a layer of 4 to 6 cm organic manure on the bottom as the base fertilizer. Next, add a layer of soil on top of the manure to avoid the chinese juniper roots coming into direct contact with the fertilizer, so the highly concentrated fertilizer doesn’t dehydrate the roots. Place the plant into the pit, backfill the soil to fully cover the roots, and press the soil firmly. Water thoroughly.
Pruning
Chinese juniper doesn’t need much pruning. For a plumper look, prune top buds in daily care to promote the growth of lateral buds. In the winter, when the plant is dormant, prune old, dry, pest- and disease-infected branches. Trimming excessively dense branches can improve the plant’s internal ventilation and light permeability, and reduce the chance of pests and disease.
Propagation
Chinese juniper can be propagated by cutting. Cutting can take place at any time except in the winter and is best performed at 20 to 30 ℃. Overly high or low temperatures can cause the branches to rot or make it difficult to grow roots.
Choose robust new branches that sprouted in the current year, and trim them to 5 to 15 cm-long segments, each with more than 3 buds. The top of the branch segment should be cut level, with the incision 1 cm away from the first bud. The bottom of the segment should be cut obliquely, with the incision 5 mm away from the last bud. Use sharp gardening scissors that can make flat, smooth incisions, minimizing harm to the branches.
Transplanting
For optimal growth, chinese juniper transplanting should ideally occur between late winter and early spring (S1-S3), this affords the plant ample time to establish before the stress of summer. Ensure a sunny location with well-drained soil for successful acclimation. Remember, taking care to avoid root damage during the process is paramount.
Overwintering
Although chinese juniper is quite cold-resistant, young and newly-grown plants need protective winter measures. It’s best to cover the plants’ roots with hay, soil, or plastic film in the early winter, and paint their trunks white with water-based latex paint.
If not painted white, a dark-colored tree trunk absorbs heat from winter daylight, bringing the trunk temperature up. Then it drops drastically at night. When the temperature difference between day and night gets too big, the bark could fissure, making the chinese juniper more vulnerable to pests and diseases.
III. Chinese Juniper Groundcovers
Many of the Chinese juniper groundcover varieties are crosses between J. chinensis and J. sabina. The most popular varieties for this purpose grow only 2 to 4 feet (61 cm. to 1 m.) tall and spread 4 feet (1 m.) wide or more. If you plan on growing a Chinese juniper plant as a groundcover, look for one of these cultivars:
- ‘Procumbens,’ or Japanese garden juniper, grows 2 feet (61 cm.) tall with a spread of up to 12 feet (4 m.). The stiff horizontal branches are covered with blue-green, wispy-looking foliage.
- ‘Emerald Sea’ and ‘Blue Pacific’ are members of a group called Shore Junipers. They grow 12 to 18 inches (31-46 cm.) tall with a spread of 6 feet (2 m.) or more. Their salt tolerance makes them a very popular seaside plant.
- ‘Gold Coast’ grows 3 feet (1 m.) tall and 5 feet (1.5 m.) wide. It has unusual, gold-tinted foliage.
IV. Uses and Benefits
Chinese juniper can be planted alone or in clusters. It has a number of important uses in landscaping, such as creating ground cover, shade with its heavy foliage, hedges, or privacy screens and is also used for specimen plantings. Prized for its dark green, thick growth, it is a good fit for ornamental gardens and general landscaping. Its companion plants include ornamental grass, which makes a good contrast, and Hydrangeas, whose blooms complement its appearance.
V. Harvesting and Storage
When Chinese juniper branches are harvested and placed in vases for viewing, they can last for 2 months. Early-morning harvest is best to avoid branches withering due to dehydration. Cut the branches off at a 45° inclined angle with a pair of sharp gardening scissors and quickly put them in clean water to prevent water loss.
