Lesson #4:  CREATING PREPARED BONSAI STOCK!

               DO NOT TRAIN PLANTS THAT ARE NOT HEALTHY AND GROWING VIGOROUSLY!  Bonsai training places large stresses on trees and weak trees quickly die.  It is necessary to balance the branch and foliage growth with the capabilities of the root system to provide the necessary elements for growth. Many bonsai instructors retain as many roots as possible rather than focusing on creating an ideal root system which is needed for the long-term health of a tree.

                 When I first began evening adult education beginner bonsai classes in the 1960's, students had a very difficult time obtaining suitable plant materials in the local garden shops.   Most of the early work was teaching how to prepare the plants and I let them work on my trees until theirs were ready for training. Fuku-Bonsai actually began as a part-time backyard nursery to be able to provide prepared bonsai stock for bonsai classes.   I believe my students were successful primarily because of the emphasis on creating healthy plants with ideal root systems. With my methods,  as much as 75% or more of the old media is exchanged when repotting.  This produces strong growth and faster bonsai development. The best bonsai are healthy trees that are growing vigorously.

                Some professional bonsai nurseries provide high quality material that can immediately be used in workshops.  Unfortunately, in most areas of the country,  there are no specialty bonsai nurseries, or existing bonsai nurseries will not offer prepared bonsai stock because the difficult part is done and it's more profitable to train to the next stage and sell bonsai.  Each year, Fuku-Bonsai is increasingly supplying trees for individual and group True Indoor Bonsai workshops throughout the United States.   These are for those who want to grow bonsai indoors throughout the year in homes and offices or grow them outdoors during warmer seasons.  For those who want to train the outdoor trees that grow naturally in your area and who cannot obtain them as "prepared bonsai stock,"  there's no choice but to prepare the trees yourselves.  This is how it is done.

                This technique applies primarily to those trees that will send out new growth on old wood.   Many plants including pines and junipers need to have some foliage left on each branch and such trees cannot easily be reduced.  Recently at a garden shop a plant caught my eye that I hadn't trained as bonsai.  I know it had potential, but somehow never got around to it.  So I purchased two badly pot-bound plants that had the lower branches dying out. 

Duranta 1 72dpi 4x3 flowers berries.jpg (21848 bytes)
CONVERTING NURSERY PLANTS TO
PREPARED BONSAI STOCK

        Golden Dewdrop (Duranta repens) is a tropical shrub that grows about 12' tall.  It's not shade tolerant and not suitable for growing indoors. Lower branches that are shaded become weak and die-out. Such trees tend to have an umbrella-type crown with the leaves on the upper and outer edges and with a lot of dead twigs under the leafy outer canopy.  It has attractive small 1/4" lavender flowers that turn into berries.  The strings of berries begin green and become a golden yellow.  There are berries on the tree for much of the year and it adds a nice accent to a tropical outdoor bonsai collection.

 

Duranta 2 72dpi 4x3 potting 1.jpg (27711 bytes)          The plant was in a 6" nursery pot, heavily pruned back, and removed from the pot. Roots were growing around and around the pot. Roots were also circling the bottom and actually building up a thick layer that was pushing the plant up!  The potting media was about 50% volcanic cinder aggregate and sponge rock and 50% organic potting media. 

         When you see major root growth in the part of the pot this is generally drier, the plant is telling you that the potting mixture is holding too much water. If roots are only at the bottom of the pot, the media is not holding enough water moisture and roots run to the bottom where water collects. If roots are evenly distributed throughout the pot, it's an appropriate potting media.   Examination of the original potting media will provide clues to adjust the potting media to use in repotting.

 

Duranta 3 72dpi 4x3 potting 2.jpg (31703 bytes)         If this tree is trained in its present condition,  you'll get less than optimum regrowth and the tree may die.  It is necessary to first get the root system growing effectively as over 90% of the roots of this plant must be cut away.  I had cut back more that 80% of the top growth to balance the expected root loss.

        To remove the unsuitable roots quickly,   with a heavy-duty pruner,  starting from the top, shove the pruner into the side of the root mass for about one inch and cut through.  Go down a bit and repeat until you've cut through the full height.  Cut through the outer one inch on four sides and the bottom of the root ball.  With a root hook,  work down one section at a time and pull away a section of the circling roots.

 

Duranta 4 72dpi 4x3 potting 3.jpg (34258 bytes)         The one inch deep vertical and bottom cuts through the root mass allowed pulling off the outer circling roots fairly easily and quickly.  There is no value in patiently untangling one layer at a time. In just a few minutes,  most of what would be long roots have been removed and the root mass became about one fourth of its original size with more to be removed.
Duranta 5 72dpi 4x3 potting 4.jpg (45028 bytes)          Once the circling roots are off,   use the root hook to carefully examine the roots near the trunk.  Keep exposing the trunk and removing small roots until you find larger thicker roots that are really what should have been the surface roots.  Most nurseries pot plants deeper so the potting media keeps the plant upright and it is very common to see the future bonsai surface roots near the bottom of the pot! 

         Generally bonsai nurseries pot so surface roots are exposed.  This is one of the major objectives in converting regular nursery stock to prepared bonsai stock. It exposes the full trunk line to aid in developing a styling plan. 

 

Duranta 6 72dpi 4x3 potting 5.jpg (35501 bytes)           With the smaller roots removed, the truck appears longer and thicker!  I turned the root ball over and pruned away roots that were growing downwards.  In carefully examining the root ball,  pull at each root that has been cut and often you can remove sections that had been pruned earlier.  In this case, I ended up with about 5% to 10% of the original roots.  But these surface roots and the fine hair roots near to the base of the trunk are the most important.

          Notice that what appeared to be a three trunked tree is really a tree with two branches coming out at the same height and the middle branch will be removed.  Note also that what appeared to be a 1/2" thick trunk is a 1" thick trunk base with a nice surface root distribution.   When it is necessary to remove so many roots, prune back the top growth so as not to overload the root system. Keep the newly potted plant in a higher humidity shaded area as you would treat an unrooted cutting until it begins to grow again.

 

Duranta 7 72dpi 4x3 potting 6.jpg (33325 bytes)        Prepare the pot by setting the tie-down wires, building and tamping down a mound of coarse bottom aggregate that connects all the bottom drain holes.  Insert a piece of plastic sheet film that will cover about half the pot surface and place it over the coarse hill.   Fill with body potting mix along the sides up to the top of the plastic and tamp down with the bottom of a can. 

       The photo shows the coarse mound covered with a plastic sheet film and potting media filled and tamped down on the left side of the pot and the plant placed in position.  The right side does not yet have body media.   The plant will actually be positioned on top of an almost filled pot.

 

Duranta 8 72dpi 4x3 potting 7 end.jpg (27786 bytes)       By tamping down before positioning the plant, the portion below the pot is already firm. After adding body media to the right side and tamping it down firmly,  add a handful of media where the plant will be placed, force it down firmly, and secure it with the tie-wires. Add a little body media to just barely cover the roots. With a trowel press down and even the surface and do any additional pruning.

     Place the potted plant into a pan of water and allow the water to totally saturate the media in the pot. Drain and with the trowel, press down and even out the surface.  At this point, if you plan to water carefully by bottom saturation or with a fine water spray, you can add a thin later of fine coffee grain size aggregate to seal and dress the surface. If you have a large collection and will be watering with a larger water nozzle,  pile an inch or two layer of crushed rock to serve as a mulch to protect the roots until they are established. 

                If your tree survives,  in a few months you'll see very vigorous growth as the roots make their way into the new pot.  The pot is fairly large as I want to build a larger bonsai for the collection.  But notice that the root system was placed over just a small amount of potting media that is over the plastic sheet.  The plastic sheet will prevent any and all roots from going down directly to the center of the pot.  Roots will have to go out, then down to reach most of the body media and this will produce a shallow root system but one in which the surface roots will thicken and are fairly long. 

                The future bonsai will likely be a saikei-type landscape with the base of the tree placed about 12 inches above the pot.  It will be trained low and wide to form a leafy canopy with the roots running down crevices between the rocks and entering the pot below.  Branches will be allowed to grow out from time to time as flowers and berries form on new growth only.   I may get a few more smaller trees to be able to create a multiple tree landscape.   Because the arrangement utilizes some taller rocks,  it will appear larger even though the trees are young.  It will be attractive with beautiful flowers and berries!

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REVIEW & CONCLUSION

                At this stage, actual training has not yet begun.  But in my mind, I already have a good idea of what will be created.  More importantly, I know what kind of root system I have.  This tree will likely be the main tree in an arrangement and I now know the features of the trunk and can pick up a few more trees that have similar character and begin to look for specific rocks that I'll be needing.  But when the arrangement is actually done,  there will be excellent odds of success because of the preparatory work that was done today.  It is tempting to omit this preparation activity and go straight into training newly acquired plants.  Unfortunately enthusiasm and aggressive training techniques combined with weak trees often result in failures. 

                The late American bonsai master John Naka often said:  "A live donkey is better than a dead doctor!"   I agree that the goal of training a bonsai is to have a healthy creation that will bring joy for many years.  It is necessary to place great emphasis on assuring the health of a tree BEFORE training begins.  Root management is a major priority at Fuku-Bonsai.  By removing major roots that grow downwards and the remaining roots primarily being surface roots,  we develop trees that have outstanding trunk buttressing and prominent surface roots.  These are required for the bonsai to be strongly bonded to the earth rather than appear to be a telephone post sticking out of the ground.

                Our method to prepare bonsai stock creates a very shallow root system and will routinely and safely allow removal and replacement of 75% or more of the potting media.  It will not be necessary to repot as often. The plants will grow naturally and the fertilizing is less important.  We use the plastic sheet to create a shallow root system and at any time, the plant can be safely planted into a very shallow bonsai pot. There are various ways to treat prepared bonsai stock.

               ACCELERATED GROWTH TRAINING.   In very early stages such as the example above, the tree could have been placed in a standard deep nursery pot.  If I wanted a future bonsai of about 18" tall, I'd specify an 18" diameter nursery pot.  Fill half with coarse material and form a hill. Position the plastic sheet and add and tamp down potting media to the level of the plastic sheet.  Position the pruned plant and add only enough potting media to cover the roots and tamp down.  Add enough crushed rock chips to cover the roots and to protect the roots during rapid watering. The rock chips on the top serve as a mulch and helps to hold down weeds.  The very thick drainage layer creates a perched water table and holds water vapor so watering skill is less critical.   When its time to train the tree, the coarse materials on the top and bottom can easily and quickly be removed. 

                When trees are placed into this situation, they become very healthy and grow vigorously.  Placed in nursery beds or on large benches, they are heavily fertilized with very little care. From time to time, they may be cut back dramatically, and after several such reductions, an impressive stocky trunk with prominent root buttressing begins to form.  This has become the trademark of Fuku-Bonsai trees and it is a joy to train such high potential trees. 

                Bonsai is not a race and while it is necessary to be efficient in a bonsai nursery, efficiency usually means doing the right things at the right time.  Speed in wiring is worthless if not done properly or if better results could be obtained by pruning techniques. 

                Bonsai is not about obtaining old trees, large trees, or thick-trunked trees.  I've seen too many books that recommend growing trees in the ground or in large pots to thicken the trunks.  But without a root control strategy, digging them out will be difficult and high-risk.  Without cutting them back, all you'll have is a thick trunk without any taper.  Without prepared bonsai stock and accelerated growth techniques, too many bonsai are simply old stunted skinny trees. 

                "Prepared bonsai stock" is a very infrequently used term simply because most "starter stock" is offered for sale as cheaply as possible.   I hope that this lesson proves helpful in giving you an understanding that creating bonsai is a very disciplined logical process.  I strongly recommend incorporation a session to properly prepare your bonsai stock as a prerequisite to your first major bonsai training session.  In some respects, it requires patience.  If you enjoy bonsai enough and grow enough trees,  there will always be something to do.   In enjoying a satisfying bonsai hobby whenever you have a bit of free time, you won't even bother talking about all that patience that non-bonsai people talk about!

                All best wishes for YOUR success!  ~~~David W. Fukumoto (August 14, 2004)

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