Though no bonsai is easy to train or care for, pine is among the easier species. More tolerant to drying, they adapt well to a pot and often require only regular trimming and biannual repotting.
In the wild, pine commonly grow to 50 feet or more with trunks that are a foot in diameter and larger. Yet they make excellent bonsai trees and look stellar in miniature form. Because of their naturally straight trunks and symmetrical branch arrangements they are well suited to the formal upright (chokkan) style.
In the chokkan style, the trunk is straight and rises vertically from the base, in contrast to the cascade (kengai) that is both curved and grows horizontally across the surface. The chokkan thus makes a good starter species for budding bonsai artists.
Bonsai trees are not a dwarf variety, but a full-sized species that has been carefully trained to emulate conditions in the wild on a very small scale. White pine bonsai, therefore, will have the same characteristics as the full grown variety.
White pine have blue-green needles that form in bunches of five, growing from a small bud. Branches grow in a circular pattern, looking down at the tree from above, with several levels around the tree at intervals up the trunk.
A healthy tree looks healthy, especially in the spring when new growth appears. Needles will be a brighter green and start lengthening. Full-sized pines can add two feet or more to their height during the season. You’ll want to remove or reduce some of the new shoots during this period every year or two.
Repotting can be carried out during spring but can wait as late as early autumn, after the summer heat has cooled.
During repotting ensure there is good drainage when you’re done. Pines tolerate dryer soil much better than over-watering. A mixture of 50% soil, 10% peat and 40% coarse sand works well for many, but there are many variations on the material and relative amounts.
Repotting is a good time for root trimming, but be conservative. Pines need a deep pot in order to grow a deep root system for stability. No more than 1/3 of the root should be cut off during the procedure.
Branch pruning is best carried out during late autumn.
It’s common for some of the needles to become brown and fall off in the summer. This needn’t be cause for concern unless the tree is diseased.
Check for large hemispheres of very dark growth on the branch that can indicate the presence of a tumor. If there are none, and only a small percentage of the needles are brown, the condition may well be normal.
Aphids and mealy bugs are common pests, but easily controlled by a commercial or home-grown mixture. Often a slight misting with a dilute liquid dishwashing detergent will take care of the problem temporarily. The needles should be misted with plain water the day after.
Pines can be watered daily provided there is very good drainage, but every other day is fine. Feeding should be done every two to four weeks from early to late spring and again at the end of summer to early autumn. This coincides with the pine’s active growing seasons.