How to cultivate Dragon Juniper? Latest cultivation techniques and methods tutorial
Dragon Juniper belongs to the Cupressaceae family, genus Juniperus. Aliases: Raolongbai, Luosibai. It originates from southern Northeast China, North China, Japan, Korea and other places, and is cultivated in cities throughout southern North China and East China. In the same genus, Golden Dragon Juniper has all scale leaves, with yellow leaves at the branch tips; Prostrate Dragon Juniper has no upright trunk, with the plant spreading flat on the ground, mostly scale leaves.
Biological Habits
Dragon Juniper belongs to the Cupressaceae family and is a cultivated variety of Chinese Juniper. It is an evergreen tree, reaching up to 8 m in height, with a straight trunk and a narrow cylindrical tree shape. The branchlets are twisted and extend upward, hence its name. The branchlets are dense, with densely growing leaves, all of which are scale leaves. Young leaves are pale yellow-green, turning emerald green when mature. The cones are blue-green, with a slightly powdery white surface.
Dragon Juniper prefers deep, fertile soil and requires good drainage. It dislikes damp, waterlogged conditions, otherwise it will cause yellowing of leaves and poor growth. It grows relatively slowly when young, speeds up after 3-4 years, and after the trunk reaches 3 m in height, its growth vigor gradually weakens.
Dragon Juniper prefers sunlight. It grows well in places with good drainage and deep soil. It has strong drought tolerance; in summer and autumn, as long as the root zone or seedbed is mulched, it rarely dies even without watering for drought resistance. However, to promote growth, with frequent fertilizer and water, its annual growth can increase by up to 50 cm. The main branches of Dragon Juniper have strong extending ability, but in regions south of the Yangtze River they do not spread outward but spiral upward around the trunk. The lateral branches are closely arranged, and the whole tree resembles two dragons embracing a pillar. Therefore, the lower branches should be properly preserved and must not be pruned or damaged at will, otherwise it will form bare-legged seedlings and greatly damage its appearance. So generally no pruning is done, allowing it to grow naturally.
Besides growing naturally into a conical shape, Dragon Juniper can also be bent, kneaded, and tied into animal shapes such as dragons, horses, lions, and elephants. Some are pruned into spherical, drum, or hemispherical shapes, planted singly or in rows, or in groups in courtyards. Some are planted as hedges and shaped and pruned into flat, rounded-ridge forms, which can show its low, full, delicate, and fine characteristics. The lateral branches of Dragon Juniper twist and spiral around the trunk, giving it a unique style and high ornamental value. It is widely cultivated throughout China.
Cultivation Management
Dragon Juniper is customarily propagated asexually, with methods including approach grafting, branch grafting, cuttings, and layering, each with its own advantages, described as follows:
1. Approach grafting: Approach grafting has a high survival rate and produces seedlings quickly. The disadvantages are limited propagation quantity, and the procedure and management are rather troublesome. Because the mother tree is tall, operation is even more inconvenient, but for small-scale propagation, this method can still be used. The rootstock for approach grafting can be Chinese Juniper, Sabina chinensis 'Pyramidalis', Platycladus orientalis, or Chamaecyparis pisifera. It is carried out in March-April, and by August-September the union has fully healed, so it can be cut from the mother plant and transplanted. For specific operations, please refer to the article "Approach Grafting".
2. Early spring branch grafting: In early spring, in February, use 2-year-old Platycladus orientalis as the rootstock, and select robust, pest-free 1-2-year-old branches of Dragon Juniper as scions, 5-10 cm long. Remove the needles from the lower 2-3 cm. Make a straight cut on one side, 2-3 cm long, and a slanted cut on the opposite side, 2-4 cm long; the rootstock can be headed back at the grafting point, then make a straight cut from one side of the cross-section, 2-3 cm long. Note that both cuts should include a little xylem. Then insert the prepared scion into the rootstock, align the cambium layers on one side, and tie the joint tightly with plastic film. To prevent the scion from losing water and dying before survival, a small plastic bag can be placed over the scion. After about 2 months, when the apical bud of the scion sprouts, it proves that the wound has healed well. The bag can then be removed and normal management resumed. In addition, during the growing season, bark-tearing inlay grafting can be used. This grafting method also has a very high survival rate.
Propagation Methods
Dragon Juniper is a valuable garden tree. Its crown is cylindrical, like a coiled dragon, and shaped like a pagoda. It is suitable for planting around high-rise plazas or for potted arrangement. It has the ability to absorb various harmful gases and has a dust-removal effect. Although Dragon Juniper can produce seeds, they do not germinate easily. Propagation methods are mainly cuttings and grafting. For graft propagation of Dragon Juniper, spring is suitable from mid-February to early March, and autumn can also be done from late September to early October. Using 2-year-old Platycladus orientalis as rootstock, the grafting methods include:
1. Field grafting: The aboveground part of the rootstock should be retained. Remove the soil from the root collar area to a depth of 3-5 cm, and cut the rootstock to about one-half deep. Select the middle section of a 2-year-old branch as the scion, about 8 cm long. Remove one-third of the needles at the base. Cut one side of the cut surface to 1.5-2 cm long, and the other side to about 0.6 cm. Insert the scion into the rootstock cut, align the cambium layers of both, tie tightly with plastic film, and mound soil 3-5 cm high. Cover with grass to prevent drought, and also set up a frame with a curtain for temporary shade.
2. Digging grafting: After digging up the rootstock, properly trim the roots and branches. The digging grafting method is the same as field grafting, but after grafting it must be planted promptly, with soil mounded to 3 cm above the top. After grafting, Dragon Juniper heals and survives rather slowly. Spring grafting begins to heal in May, so the rootstock branches and leaves should be gradually pruned away. After grafting, besides proper shading, preventing dry wind, and maintaining a certain humidity, within half a month after grafting, rainwater intrusion must also be prevented. The general survival rate can reach over 75%.
Pest and Disease Control
Dragon Juniper has relatively few diseases. Besides the above-mentioned pear rust, the common one is violet root rot, which easily occurs when the cutting seedbed medium is unclean or reused. It can be controlled according to the methods described above. Among common pests is the bagworm moth. In early June, before the larvae have spread, spray 98% crystallized trichlorfon at 1000 times dilution to control it.