SEASONAL SUGGESTIONS

NO. 92--MARCH / APRIL--2005

REPOTTING, REFINEMENT AND REVIVAL

By Marty Mann

The time for reflection and study of your trees is never over. Once the dormant period passes, it’s important to begin the repotting activities of early spring. March and April is the time, just as the buds begin to move with the warmth of the season. Start with your evergreen trees and conifers in March since they tend to be stronger during the winter months and can handle the shock of transplanting and severe root disturbance. It’s generally better to work on deciduous trees later in April when their activities come to life.

After a welcome rainy season, prepare for a serious period of repotting. It’s time to energize your thoughts and efforts. If you have already created your supply of good basic potting soil and clean pots, you should be ready to go.

Your projects can be threefold:

            • Move pre-trained material from nursery cans to selected bonsai pots, either for further training or for shows.

            • Transfer trees that are already potted into larger and/or more decorative pots due to changes in the basic shape, size or design of the trees.

            • Repot trees that are ready to be refreshed with new soil. Remove excessive root growth to generally improve their health.

The process of potting and repotting is very important at this time. Part of the responsibility of maintaining an attractive and healthy bonsai collection is the never-ending process of providing the proper growing envi­ronment. The best guideline is not just the question of the recommended time to repot, but more so, the need to repot based upon the condition of the trees. Depending upon the particular weather conditions in your area during recent weeks, signs of growing activity may have already begun. It’s best to repot before any significant signs of bud swelling has started. This is especially true of fruiting and flowering varieties. Fruiting and deciduous trees benefit from annual or frequent repotting. Don't overlook the smaller Shohin trees. It’s even more important to be watchful of this class of bonsai since they will quickly reflect your ne­glect.

Bonsai, ready for repotting should be somewhat on the dry side. The trees are easier to remove from the pot. The combing of the root ball, after cutting away the traditional 1/3, free the fine roots and encourage regrowth. While repotting, don’t allow the fine roots to be exposed to the sun or drying winds-keep a spray bottle handy. Be sure that the new soil mix has been screened to remove harmful fine dust. Newly potted material are kept in partial shade for a week or so and then moved into full sun to allow the roots to redevelop.

It's a good idea to include a small amount of bone meal and Ironite in the soil mix­ture to encourage development of new fine rootage. There is a differ­ence of opinion as to the value of including cottonseed meal at this time, however we believe that this fertilizer is better applied a month or so later since early feeding can be harmful to new growth. Cottonseed meal is a slow starter before it adds any nutrient benefit to the plant. Repotted plants may be fed as soon as signs of new growth are apparent. A suggested mix is 75% cottonseed meal / 25% bone meal.

Newly potted trees should be shaded from direct sun until new growth begins. By moving trees into sunny areas, it will stimulate the growth of foliage. Newly potted trees should first be allowed to develop new fine rootage that can then support new foliage. When new growth is evident, it’s time to begin light fertilization. Full sun encourages smaller leaves and shorter internodes.

Early bloomers such as Forsythia, Sasanqua Camellias and Quince develop during early spring months. After flowers have faded, trees are pruned to restore shape, allow new growth and bud setting. Azaleas are bare rooted and repotted in March. Be sure to comb out as much of the old soil or growing medium peat without destroying the fine root system. Incorporate as much new coarse azalea soil mix as you can when repotting to develop strong healthy new roots and improve acidity.  

Finally, prepare selected trees for display at the many spring bonsai shows held throughout the state. Select your best tree(s)--be critical of their appearance. Show trees should be free of any infections and should not show signs of ill health. Pots should be clean. Plants surface must be cleared of trash and very heavy layers of moss. Spring is usually the time when most trees look their very best.

Remember----

For every action there is an equal and opposite criticism.
Doesn’t this seem to apply to bonsai?  The best way to escape your problem is to solve it. 

Marty Mann