Pine (pinus) is a popular evergreen conifer for making bonsai. Pine, Prunus mume (flowering apricot), and bamboo are referred to as the “three gentlemen” garden trees in China.
Japanese Black Pine (Pinus thunbergii)
This is the most popular pine for bonsai in the U.S., although five-needle pine (Pinus parviflora) is also highly desirable. Both will be discussed here, with differences pointed out along the way.
Japanese Black Pine is native to Japan and Korea and has naturalized in parts of China and Oregon.
Distinctive features of the Japanese Black Pine include paired needles and silky white candles. Mikawa and Arakawa varieties, found in Japan’s coastal and inland sea areas, are the most desirable. Mikawa pines are known for producing bonsai with excellent ramification, while Arakawa pines have a rough, patterned bark.
Japanese Black Pine should not be confused with the Australian Pinus nigra, also referred to as black pine and occasionally used for bonsai.
Five-Needle Pine (Pinus parviflora)
This is native to Japan and Korea, has clusters of five needles with a soft, green, silvery appearance. This highly desirable bonsai material is especially valued in Japan for its venerable specimens. Dwarf varieties with short, straight needles are preferred over those with long, twisted needles. Named dwarf cultivars with short, straight needles are often grafted.
Collecting
Your best options are starting with a potted nursery tree, local bonsai show tree sales, or a reputable mail-order company. If you have the time (about 10 years), you can start from collected seeds. While cuttings are problematic, air-layering is possible.
Buy mature trees with desirable characteristics, such as black pines with rough bark and five-needle pines with short, straight needles.
Avoid grafted trees unless the graft is very low to prevent an unsightly union.
Black pines can be found as small seedlings or in larger containers up to 48-inch boxes. To ensure lower branches for styling, you may need to settle for a tree in a 5-gallon or smaller container.
Five-needle pines are most suitable for making formal upright or clump-style bonsai because their branches tend to have the same diameter at all heights unless training begins at a young age.
You can also get a head start by collecting mature landscaping trees from gardens or finding naturalized specimens in the wild. Styled trees can often be purchased at bonsai club sales.
Other species, such as Scots Pine (Pinus sylvestris), Mugo Pine, and most pine varieties, can also be made into bonsai. However, reducing the needle length of long-needle pines like Monterey or Ponderosa pines is challenging.
Environment
Japanese Black Pine and five-needle pine are vigorous growers with strong roots, thriving in many climates. Keep pine bonsai in full sun, as shade will cause them to decline over time.
Rotate your tree occasionally to ensure even exposure to sunlight for symmetrical growth.
Pine bonsai need ample moisture and root aeration, so they should not be planted in soggy soil. The standard BH mix of equal parts sandy loam, peat moss, and perlite works well. If your pot is very deep or your climate is particularly wet, consider adding an additional part of coarse sand for increased aeration.
Styling
Black pine and five-needle pine are vigorous growers and suitable for almost any style. Like most conifers, their branches are of similar diameter along the trunk, making them well-suited to upright styles.
Five-needle pines, in particular, are often styled as multiple trunk clumps, as their clustered candle growth lends itself to this aesthetic.
Trimming and Pruning
Both black pine and five-needle pine produce buds in clusters at the end of a mature candle. Cut off all excess candles, leaving one or two in the desired direction of growth.
The mature needles of five-needle pines will reach nearly the same length as the candles you allow to grow. However, for black pines, needle length is determined by the length of the candle when it is cut. Cut each remaining candle to the desired length to achieve needles of uniform size.
Keep in mind that conifers, including pine, do not backbud. A branch without green growth will die back.
Wiring
Use guy wires to simulate the drooping effect of thicker branches. Wire smaller branches loosely but firmly to hold their shape, and remove the wire promptly to prevent girdling.
Pot and Repotting
Use a mix of equal parts sandy loam, coarse sand, peat moss, and perlite. Add an extra part of coarse sand for deep pots or wet climates. Incorporate root-pruning mesh to prevent rootbound issues.
Repotting should be done in late fall or early spring, depending on your climate. Look for swelling buds as a signal to repot.
Maintenance
There are no special requirements for maintaining pine bonsai. Some believe high altitude pine trees, like Pondarosa, need a cold winter to be long lived.
Watering
Water daily, ensuring thorough saturation so the root ball absorbs sufficient moisture. Bonsai pots are shallow, allowing excess water to evaporate quickly, so overwatering is unlikely.
Fertilizing
Use monthly applications of fish emulsion, chicken manure pellets, Miracle-Gro, or slow-release fertilizer.
Pest Management
Pine trees are generally disease- and pest-free when kept clean.
Propagation
Black Pine
Black pines can be grown from seeds collected from cones in the fall. Select mother trees with rough bark for a higher percentage of offspring with desirable characteristics.
Black pines can also be air-layered using one-year-old semi-hardened wood, although rooting may take 10-18 months. Cork pines have been successfully propagated from cuttings, though with a low success rate.
Five-Needle Pine
Five-needle pines are readily propagated from seeds collected in the fall. Choose mother trees with short, straight needles to increase the likelihood of desirable traits.
Five-needle pines can also be propagated from semi-hardened tips about 3 inches long. Use rooting hormone and plant in a wet mix of coarse sand and peat moss.
Unlike black pines, five-needle pines are more easily air-layered.
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