Bonsai Reference - Spring

For the past months, we have experienced the relative slowdown of day-to-day bonsai activities during the winter of dormancy. Before the real work of potting, repotting, and redesign begins, certain activities must be attended to in order to stabilize the trees and provide them with the best possible start-up.

Now is the time to renew the regular schedule of fertilizing and watering. Special attention should be given to the trees which have been potted for some time. Most of their soil nutrients have been lost due to winter rains and reduced growing activity. Use a slow release fertilizer for early spring feeding. Give the new buds a chance to push out and new rootage to develop. As the weather begins to warm, the insect and fungus activity also awakens. Use MalathionŽ to destroy the eggs of most of the active insects. Use SevinŽ or other systemic insecticides to destroy the young larvae of the chewing predators. This will also affect those insects which destroy new growth by sucking sap and feeding on young buds. Use BenomylŽ, BravoŽ, or DaconilŽ to kill mildew or other signs of fungus on the foliage and the tree bark. An application of SubdueŽ will destroy fungus growth in the root system and soil if used as a drench. Be sure to check the manufacturers' instructions on all chemical products. Avoid overhead or heavy watering while treating the live material.

The prime time for repotting activities is March and April. It is advisable to remove portions of the old foliage as well as the heavier old roots to encourage new growth. Root divisions which are formed whenever a root cut takes place will provide for better nutrient absorption. Branch trimming allows new branch divisions and desired branch twiggyness. Deciduous trees such as Japanese maple, trident maple, gingko and liquid amber can now be trimmed. Flowering and fruiting trees such as pomegranates, ume, plum, apple, quince, and bougainvillea should not be trimmed in early spring since this destroys the new forming flower buds. If you wait too long into late April, it is prudent to hold off until the new spring growth has hardened, and the woody branches are more liquified. If you choose to wait until May to do any serious pruning, then control any rampant growth by pinching and nipping the terminal buds on each branch. This restraint will encourage the formation of side branches and create a more dense foliage mass.

Watch the development of bar branches on maples and other trees which normally grow opposite leaf and branch groups on the secondary and tertiary branches. Eliminate downers and uppers growing on the branches of young material. This will allow for better light penetration.

March is an excellent time to move nursery material up from smaller pots or one-gallon cans into larger growing containers. Try to keep your large material in shallow pots or cans ratherthan deep containers. The use of Mexican clay pots rather than plastic is highly recommended. Plants like the porous walls which allow for better aeration. This type of container permits spreading of fine root formations in anticipation of the shallow bonsai pots which will be their future home. Newly potted trees, whether in training cans or bonsai pots, will develop best if exposed to the warmth of the spring sunshine and full light conditions. This exposure accelerates new root and foliage formation.

Give the repotting activity a sequence of priorities. Conifers, such as spruce, fir, and cypress can be done first. Wait until later in April, early May, or June to trim pine candles to obtain shorter needles. Deciduous trees can be repotted throughout this period, but try to do it before new buds have opened. Other varieties such as junipers, bamboo, and pomegranates can also be potted now.

Small amounts of bone-meal may be mixed with fresh potting soil. The presence of this slow-acting food will provide essential nutrients to new root systems. Bone-meal is high in phosphoric acid (formula 1-30-0) and will neutralize the salt accumulations in the soil. A regular feeding of cottonseed meal, also mixed with some bone-meal (75%-25%) will provide potash (formula 7-3-1) and restore acidity as needed. Another newly discovered feeding addition being used by many bonsaiists is the addition of IroniteŽ (approximately 10%). This is a granular version of a highly soluble iron supplement which supplies numerous important minerals and adds acidity to encourage green growth.

In addition to the training and care of bonsai, this is an excellent time for air-layering. Spring is the time when the fastest growth takes place, new buds are forming, and propagation conditions are at their best. Look around your garden. Look at your training stock or mature bonsai. Pick a branch division that will create an almost instant bonsai miniature. Air-layering can succeed on maples, azaleas, liquid amber, pomegranates, and elms. Here is a basic procedure for a high success rate of air-layering.

Early in the growing season, cut a round band of bark, 1-1/2 times the diameter of the branch from which the air-layer is being taken. Cut deep enough to penetrate the cambium layer and into the heartwood. If any cambium tissue is allowed to remain, it will permit the tree to rejoin the channel of nutrient flow and will prevent the formation of new roots at the edge of the cut.

Next, use a twist of strong copper wire to form a circle around the upper lip of the cut area. Pull tightly to strangle the trunk to prevent any nutrient flow below this area. Apply powdered RootoneŽ to the upper lip of the cut. Apply a pad of shredded sphagnum peat moss, saturated with a solution of B-1 or SuperthriveŽ and wrap the entire bulge with plastic. Tie the upper and lower edge of this ball with another twisted wire, but allow a small entry area to permit the introduction of water when the roots begin to form. Do not allow the ball to ever go dry. Several weeks may elapse before evidence of new roots appear. The time will vary with the variety of tree stock as well as the weather conditions. Inspect frequently. When the roots become clearly visible through the plastic, choose a cool day to cut the new trunk off below the ball. Plant the new tree in a well-draining soil mix. Be especially careful to prevent damage to the new roots when removing the plastic wrap. Do not disturb or remove the moss.It will, in time, disintegrate into the soil. Keep the leaf growth at a minimum to encourage continued root development as the new tree become acclimatized to its new home.