Japanese red pine is a very attractive, interesting looking specimen tree native to east Asia but currently grown all over the U.S. Keep reading to learn more Japanese red pine info, including Japanese red pine care and how to grow a Japanese red pine tree.
I. Appearance and Characteristics
Pinus densiflora, also called the Japanese red pine, the Japanese pine, or Korean red pine, is a species of pine tree native to East Asia. In China it is known as 赤松 (pinyin: chì sōng, literally “red pine”).
P. densiflora has a home range that includes Japan, the Korean Peninsula, northeastern China (Heilongjiang, Jilin, Liaoning, Shandong and northeastern Jiangsu) and the extreme southeast of Russia (in Siberia, southern Primorsky Krai).
The leaves are needle-like, 8–12 centimetres (3–4+1⁄2 inches) long, with two per fascicle. The short leaves are 5–6 cm. There are stomatal lines on both sides of the leaf, two vascular bundles, about three to nine resin canals, and fine serrations on the edge of the leaf. Branchlets with more or less white powder. Male cones are light reddish yellow, clustered in the lower part of new branches, female cones are light reddish purple, solitary or clustered in two to three clusters.
The cones are dark brown yellow or light brown yellow when mature, they descend at maturity, seed scales usually thin, seed winged. The bark is orange-red, cracked into irregular scale-like pieces. Heartwood reddish brown, sapwood light reddish yellow. The height of the tree is 20–35 metres (66–115 feet). The crown can reach 30 metres (98 feet).
“The distribution of P. densiflora in China has the following pattern of variation: the more northward it is distributed, the needles are relatively shorter, the white powder on the branchlets is sometimes less obvious or partly obvious, and the color of the cones is lighter. It is light brown yellow”.
The cones are 4–7 cm (1+1⁄2–3 in) long. It is closely related to Scots pine, differing in the longer, slender leaves which are mid-green without the glaucous-blue tone of Scots pine. This pine has become a popular ornamental and has several cultivars, but in the winter it becomes yellowish. The plant prefers full sun on well-drained, slightly acidic soil.
II. How to Grow and Care
Sunlight
The Japanese red pine can grow in both full sun and partial shade. When placed in a well-ventilated location with sufficient sunlight, the needles will be green and strong. In a hot location with insufficient sunlight, the needles will be weak and will easily turn yellow. Ideally, the plant needs around 5-6 hours of sunlight a day, with good ventilation.
Temperature
The japanese red pine is mostly native to the northern hemisphere and can withstand many challenging environmental conditions. Tolerant of temperatures ranging between -60 to 50 ℃, making it suitable for hardiness zones 11 and below, this is a plant that grows best in well-drained, deep and moist soil.
Watering
For newly planted seedlings or new plants, water once every morning and evening during hot spells in the summer. Do not water midday, as this can cause root burn or strangle. Water plants according to your individual climate and rainfall in other seasons. For mature plants, only water when they are dry, keeping in mind that these plants are drought resistant. For indoor potted plants, spray water on the surfaces of the leaves once every morning and evening when it is dry. Be careful not to provide excess water – this hinders air circulation in a pot, leading to the rotting of roots and the withering of branches and leaves.
Soil
Japanese red pine can grow in a variety of different soil types, including bare mineral soil, sandy soil, volcanic ash, calcareous soil, limestone soil, and everything from dusty soil to red soil. Since it is resistant to drought, it will even grow in barren landscapes. However, it grows best in loose, fertile, well-drained, and slightly acidic soil. In the case of too much alkalinity, needles of potted plants will turn yellow and fall, so it is best to use natural mountain soil in pots and containers.
Fertilizing
The japanese red pine likes fertilizer and should be fertilized frequently, with just a small amount each time, during its growth period. It should be fertilized once a month in late spring, early summer, and fall. A fermented organic fertilizer is most effective for promoting growth.
Generally, do not apply a nitrogen fertilizer, such as urea or human urine, because pine needles already absorb nitrogen from the air, and pine roots are sensitive to nitrogen. You would be best off with a liquid fertilizer, applying this when the soil is dry in the afternoon. Water the plant again after fertilizer application, which will help with root absorption.
Do not use fertilizers that haven’t been fermented, or those with a higher concentration; the former will burn the roots and the latter will lead to the spindling of needles and more root damage, and could even cause the back-flow of sap, leading to water loss and the withering of the plant. No fertilizer should be applied in midsummer, during severe winters, or in the rainy season in the spring.
Generally, plants in gardens should be fertilized twice during the growth periods in spring and fall. Apply an organic fertilizer once before germination in the spring and apply slightly more fertilizer in the fall to promote robust growth. Stop fertilizing after midsummer so as to prevent spindling.
Planting Instructions
Japanese red pine is best planted in early spring. Ideally, use healthy and vigorous seedlings with soils balls, as this can greatly improve the survival rate. In the case of many lateral roots, the deep main root can be cut. Otherwise, the root system should be protected to avoid damage.
plant in a high, dry, well-drained, and well-ventilated place, with loose soil. In low-lying places with accumulated water, or places with sticky soil, try building a platform or changing the soil before planting. The planting pit should be treated with a basal fertilizer before planting. Newly planted large seedlings should be supported to prevent them being blown down by the wind. Before planting, excess branches should be pruned off. Protect the plant’s shape from damage as much as possible, as this will help to restore growth at a later stage.
Ideally, plant indoor potted plants in the spring, and repot every two or three years in the late fall or early spring. Repotting too frequently will lead to the death of the plant. If the plant is growing weakly, find out the cause of this and change the flowerpot soil, or replant in a larger pot.
Cut back on water before repotting, so as to keep the soil slightly dry. Remove the soil ball from the pot, keeping it whole, and then prune away any old roots from the bottom and sides. Remove some of the old soil from the middle of the soil ball, replace with new soil, apply a small amount of basal fertilizer, and then cover the plant with new soil. Ensure a suitable pot size – a deep pot will easily accumulate water, leading to root rot.
Pruning
For an indoor potted plant, any dead, diseased or damaged branches should be removed. You can then adjust the tree’s shape by pruning branches, pinching buds, and trimming leaves, giving you a better ornamental effect. Prune the plant before all of its needles fall off, so as to obtain a compact shape, richer lateral and side branches, and a better form overall. Pruning should be done during the dormancy period, so as to prevent excess loss of sap and damage to the plant’s vigor.
For a plant in a garden, dense lateral branches should be pruned so as to improve the survival rate. Remove excess lateral branches during the vigorous growth period based on needs, focusing on encouraging the trunk to grow tall and straight. Cut off any diseased or dead branches right away, so as to prevent the spread of pathogens.
Propagation
Japanese red pine is mainly propagated by seeds or branch cuttage. For family planting or potting, cultivated seedlings or pruned potted plants can be purchased from the market. Pay attention to pests, diseases, and appearance when selecting seedlings.
Pests and Diseases
Japanese red pine is susceptible to a range of pests and diseases, including pine bark beetles and pine needle scale. Regular monitoring and treatment may be necessary to keep the tree healthy and prevent damage.
Seasonal Precautions
In the summer, hot temperatures, strong sunlight, and frequent precipitation are unfavorable to potted plants. Care management is very important at this time. In the hot noon of midsummer, shade should be provided to protect the needles from excess sunlight and leaf scorch. In the summer, the plant enters its dormancy period and grows slowly.
However, water evaporates quickly, meaning that pots can quickly turn dry in high temperatures. Generally, potted plants should be watered once every morning and evening. Provide a generous amount of water in the morning, but base your evening watering on how moist the soil is.
During a heavy shower, immediately cover the plant to avoid the loss of nutrients in the soil. Do not prune the plants in midsummer – this can cause a lot of rosin to flow out from the cut, impacting growth. In the spring, summer and winter, make sure that your plant is receiving enough sunlight. Its needles should be short, robust and green, rather than weak and yellowing.
The trees grow in the spring and fall, so keep the soil constantly moist to promote the growth of new branches and leaves. Natural water, or tap water that has been stored in a jar for several days, is best. Try to fertilize twice during the growth periods in spring and fall. Apply an organic fertilizer once before germination in the spring, and a slightly concentrated fertilizer in the fall to promote robust growth. Stop fertilizing after late fall.
III. Uses and Benefits
Strong wind resistance, P. densiflora is an excellent tree species for afforestation in stony mountains, barren soil and sandy land. The timber can be used for construction, electric poles, sleepers, ore pillars, furniture, and wood fiber industrial raw materials. The trunk is rich in resin, from which rosin and turpentine can be extracted. Essential oil can be extracted from the leaves.
In northeast China, matsutake relies on P. densiflora for growth. “Jilin Tianfozhishan National Nature Reserve/Jilin Tianfozhishan National Nature Reserve” takes Matsutake, P. densiflora and ecosystem as the main protection objects. P. densiflora wood has natural anti-corrosion and anti-mildew properties, and natural preservatives and natural wood anti-mold agents can be extracted. P. densiflora has non-stinging needles and soft branches, making it easy to shape as a penjing.
Find Where to Buy the Best Japanese Red Pine (Pinus densiflora)
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