Japanese Five Needle Pine Care Guide
Pinus parviflora, a native to Japan, is generally known in the bonsai world as Japanese Five Needle Pine, however the tree is also referred to in horticulture as Japanese White Pine, or Pinus pentaphylla. In nature the tree may reach up to 50 feet in height. This evergreen is frequently used as bonsai both in North America as well as Japan.
As indicated in the name, the needles of this species grow in sets of five, at a length of one to one and a half inches. The short, fine, tufted foliage and brown textured bark make it desirable as a bonsai subject.
Japanese Five Needle Pine prefers a temperate climate and does best when it can experience the natural weather changes associated with cooler locales. It should be grown outside in full sun.
Pinus parviflora prefers to be dryer than some bonsai. When it is time to water, do not saturate the roots. Water the top of the soil and allow the moisture to gradually seep through. As with all pines, good drainage is key, as well as adjusting the watering schedule to the particulars of your climate – temperature, humidity, and amount of direct sunlight.
An easy way to keep track of your bonsai's watering needs is to use a moisture meter. Watering errors kill more bonsai than any other cause, so taking the guesswork out of the matter can help you keep your plant healthy.
Begin feeding your Japanese Five Needle Pine in the spring, as new growth begins to appear. Administer an organic slow-release feed once a month during the growing season. Supplement with chelated iron two to three times per year. A chemical fertilizer may be used instead. Choose one made for acid-loving plants and feed every other week at half-strength.
Commmon Styles – most often seen in formal or informal upright, but the short foliage will allow for shaping into a number of forms. The trunk of the White Pine may take on a slant, especially with encouragement, giving it almost a cascade look. Because of the dense foliage an impressive canopy may be developed.
Prune branches in the late fall. Plucking can be done throughout the growing season, and should be done with an aim of shaping the foliage to the desired form. In the spring, pinch off new growth to one third its original length. Every year or two in the late spring all of the new growth may be pinched off – this will help new buds develop and can be used as a method of encouraging growth in certain areas for purposes of shaping the foliage.
The Five Needle Pine can be wired; this should be done in the fall during hard pruning. Leave the wires on for no longer than six to eight months and check regularly for signs of cutting into the bark.
The Japanese Five Needle Pine may be propagated by seeds or layering. Make sure to soak the seeds for a day or two, and discard any seeds that float in the water (these are not fertile). They can then be placed in moist sand in a cool place for a month or two before transplanting.
Young trees, up to the age of 10 years, should be repotted every two to three years. Older trees can go three to five years between transplanting. Repot either in spring before the candles have opened or in late summer to early fall, once the hottest summer weather has passed. Pines require a deeper pot than many bonsai because of their hearty root system. In addition, the Five Needle Pine's dense foliage structure makes it vulnerable to uprooting in strong winds.
Pines do not take kindly to overzealous root pruning. Be judicious, and do not allow the tree to go bare-root. Pines have a symbiotic relationship with a fungus that lives in the root ball, Mycorrhiza, and it is vital to their health. Use a well-draining, coarse soil of mostly or all inorganic material.
Insects/Pests & Diseases:
Like most pines, Japanese Five Needle can fall under attack of a number of pests like aphids, red spider mites, and mealy bugs. Mealy bugs may only be noticed upon repotting, appearing as tiny white wiggly cotton balls. There are insecticides designed specifically to cure a mealy bug problem. Other visible insects may be washed off in a gentle spray of water, or treated with a systemic insecticide.
Pines are also vulnerable to needle cast. This is a fungus causing brown, discolored needle tips and sometimes rings of discoloration around the middle of the needles. There are treatments for this however it's better to spray your Japanese Five Needle Pine bonsai with a preventative year-round.