SEASONAL SUGGESTIONS
By Marty Mann
January/February - 2001

SPRING -- REJUVENATION, NEW ENJOYMENT

Spring is a period of renewal, replanting, refinement, revival and resurrection.  It’s time to resume a regular schedule of fertilization and bonsai care, especially those trees that are potted in soil that has been leached of nutrients by winter idleness.  Now is the time to consider a serious period of repotting.  Energize your thoughts and efforts.  If you have created a supply of good basic potting soil, fertilizers and other chemicals you should be ready to go.  Are the used pots all clean?  Do you have an assortment of good new pots to select for new plantings?  Your projects can be threefold:

Part of the responsibility of maintaining an attractive and healthy bonsai collection is the never ending process of providing the proper growing envi­ronment.  Your best guideline is not just the question of the time to repot, but more so, the need to repot -- based upon the condition of the trees. Pruning and repotting stimulates the plant’s natural growth hormones and enhances the health of the tree. The particular weather conditions in your area during recent weeks may already be showing signs of growing activity.   We have had an exceptionally warm February. It is best to repot before any significant sign of bud swelling has started.  This is especially true of fruiting and flowering varieties. Most of these, as well as deciduous trees,  benefit from annual or frequent repotting.  Don’t overlook the smaller Shohin trees.  It is even more important to be watchful of this class of bonsai since they will quickly reflect your neglect.

Prioritize your work schedule.  Varieties of conifers such as Junipers, Spruce, Fir, Hinoki Cypress, etc. can by done first.  It is suggested that you wait to do Pine trees until later in April or early May. By waiting, you create shorter needle growth as the candles open.  Second, take care of the deciduous trees that are best moved while they still have tight leaf buds.  Finally, all of the Juniper varieties and the Bamboo specimens can be done.  Do not wait until late into April. Give newly potted material a chance to develop new growth in their new medium as the weather warms.

Springtime, while repotting, is a good time to improve refinement.  Study the changes that have taken place since last year.  Did you photograph your tree? Are there any branches that should be removed or rewired?  This is the time to do the much-avoided detailed secondary and tertiary branch wiring.  As the growth begins, keep the tip-pinching, bud snipping and large leaf cutting patterns in mind to keep your tree uniform and well shaped.  Take another photograph for comparison.  Guide yourself by the Isosceles triangle rule.

Repotting encourages new root development and frees constricted, root-bound material.  It’s usually unnecessary to move material into larger pots when the root development is excessive. It’s better to root prune and
provide fresh soil.  The roots do not stop growing when branches are pruned.  Pruning increases the growing activities at the tips of each cut.  New side shoots develop and redirect the plant’s energy to new capability.  It enhances the passage of nu­trients to the upper structures of the tree.

A bonsai should be somewhat dry to be ready for repotting.  This facilitates removal from a tight pot.  Unwind twisted roots that may have begun to circle the outer rim, and free them of any hardened or compacted soil.  Usually, with deciduous or conifers, it’s best to cut about 1/3 of the root ball away as the roots are freed.  Trim with a sharp cutter to reduce the ball to the repotting size.  Keep your fine roots sprayed.  Do not allow them to dry out.  Remove heavy old roots. 

This is the proper time to reposition the tree -- if it is required.  Change the height, adjust the trunk angle and add more potting soil around the root ball and work it in with your chopsticks to fill in as many air pockets as possible.  Remember to slope the surface slightly from the trunk to the lip of the pot.  Leave an indentation along the rim of the pot to prevent water run-off.  A good soaking or dunking removes destructive air pockets.  Place repotted material in semi-shade for a week or so.  Don’t water regularly but do not allow the tree to become dry.  Introduce it back to full light and warmth to encourage root and bud growth to begin.  Do not feed for 4 to 5 weeks.  March and April can be capricious months -- ranging from cool to hot.  Do not encourage too much quick growth since this will create unsightly long internodes and large leaves.  Pay particular attention to fruiting and flowering trees.  If they have been too active in directing their energy into flowers and buds then some pinching back can help them pay attention to leaves and woody branching. 

March is a very important month.  It’s the time to begin the fertilization program on established trees.  Use a slow release fertilizer just prior to signs of new growth.  Organic fertilizers such as a combination of cottonseed (75%) and bone meal (25%), give the trees a desired boost during this fast growing season.  Trees may also be given an interim push by using a liquid food like Miracle Gro® between regular monthly feedings.

Keep the nitrogen content of the fertilizer at a minimum in these early feedings.  Excessive green foliage and leaf growth weaken the flowering effort.  Use a weak application just as the flower buds begin to swell and again as they open and develop.  Plants are now growing vigorously and need to be fed regularly.  It’s better to feed more often with light applications then less often with a heavy hand.  Remember to keep fertilizers away from the trunk of the tree.  It’s better to broadcast dry fertilizer lightly over the pot sur­face and close to the edge of the pot.  Do not feed newly transplanted or repotted trees for a month or two until they are established.  Use low nitrogen, high phosphorus, fertilizers such as the slow releasing bone meal or super phosphate to keep fruit and berries from falling off prematurely.

Maintain control of new growth by pinching and nipping the terminal buds on each branch.  This forces side branches to grow.  This technique creates a more dense foliage mass and keeps the internodes of the branches shorter.  You will be rewarded with a fine twiggy tree.  Watch for the development of bar branches on maples and other trees that normally grow opposite leaf / branch groupings.  Keep new buds at any point in which the direction of new growth is desired.  Pay particular attention to the underside of a branch for downward growth as well as unnecessary upward branches.  The elimination of this growth allows better light penetration into the heart of the tree.  Excessive growth in the upper portion of the tree shades and weakens the lower branches.

New candles that have begun to form on older Pines are cut back in April.  Wait an­other month before you work on younger trees.  Pine candles indicate the presence of strong hormonal activity.  New candles generally form twice a year, in April and August.  They form clusters of from 2 to 5 candles. Usually one will dominate.  Retain only two: one as a leader and another to form the side branch.  Always remove the largest candle but do not cut the existing candles until needles just begin to open and expand.  This timing prevents excessively long internodes between last year’s branch tip and the new needle growth.  Do not make the mistake of retaining any part of the candle since new growth will be directed to the remaining fragment.  Reduce watering to  slow down the new growth but do not allow the plant’s rootage to become dry.  Keep pine needles short and strong. 

This is a good time to plant a root-over-rock bonsai.  Comb out the roots of a three to five year old tree -- one of the best varieties is the venerable Trident Maple.  Set the root ball onto a shapely, interesting rock that has deep fissures and varied surfaces and colors.  Lightly bind the roots to the rock with string (that will, in time just rot away) and pack them gently with a muck mixture to secure them and keep them damp.

Plant the complete structure into a large nursery container or in the ground.  Allow the tree to develop for a year or two to fatten the roots and encourage them to cling to and become part of the rock.  When ready, gradually begin a process of brushing away the soil from the top of the rock and exposing the roots to the light and air.  The roots will take on the texture and color of the bark of the tree.  Train the upper structure of the tree to carefully balance and compliment the rock form.  Select an apex and establish the branch positions in accordance with proper bonsai styling methods.

It is still not too late to propagate, early in March, by cuttings or grafts.  Cuttings are made with dormant material that just begin to  show spring growth -- most will do better if the material has been allowed to harden first.  Use a sandy potting mix that drains well for collected material to encourage new root growth.  Late spring is the best time to propagate tropicals such as ficus varieties.  It’s also the time to sow seeds of deciduous trees that have been kept cool in your refrigerator for stratification.   Plant seeds in March or April.  Take cuttings of junipers and prepare air-layers as well.  Use previous season’s wood.

By controlling the amount of light exposure given to young trees, you can hold back or push these transplants.  Leaf development can be slowed by keeping the material in a cool area with little sun, so they do not start to grow too soon.  This is a particularly good technique if you are timing leaves or flowers for a show.

Learn from the mistakes of others.  You can never live long enough to make all of them yourself.  Spend twice as much time listening as talking since listening is twice as hard as talking.  Enjoy your bonsai!