REBS Demonstration by Bob Shimon – San Jose Juniper

On August 27, 2019, Bob Shimon performed a demonstration for the members of the Redwood Empire Bonsai Society (REBS) on a San Jose juniper (Juniperus chinensis ‘San Jose’. Bob recently purchased the San Jose juniper from the member sales area at the August 24 and 25 REBS annual bonsai show. He said the San Jose juniper had character and interest as bonsai material for his demonstration. Some of the factors lending to character included: deadwood at the base of the trunk; a large base at the trunk; movement in the trunk; no or minimal taper in the trunk suitable for a bunjin or literati style bonsai; foliage concentrated at the top.

One of the first things to do when purchasing or beginning to work with bonsai material is to scratch away the surface soil from the base of the trunk to expose the root structure. A few inches is sufficient to observe the flaring of the trunk base. Bob saw a bunjin style bonsai within the material. He would proceed to cut and remove small interior branches. He would also remove unwanted branches and any dead branches. He said the main purpose of the demonstration material was to establish branch structure. There were two main trunks; one had to be removed as it was competing with the other and in conflict with the intended design. Bob used a sharp hand saw and removed the smaller of the two branches. What remained was a fairly long, curving branch with its foliage near the top.

Bod identified a number of smaller secondary branches that he would jin. Jin is Japanese for deadwood feature for a branch. Shari is also Japanese for a deadwood feature along the trunk of the tree. Both deadwood features are seen in nature and add to the character and age of the bonsai. Where branches were removed, Bob created jins. The jin is made from a short stub of the cut branch. A long jin is not true to nature. The best time of the season to work on creating jins and shari is when the tree sap is present.

Bob discussed a little about the horticulture for bonsai. Most bonsai require the outdoors. Exceptions are tropical and sub-tropical plants. Bonsai soil for junipers or conifers is on the dry side; usually one third pumice, one third lava rock and one third Akadama (a fired clay imported from Japan). Redwoods and deciduous require more moisture and use more Akadama. Fertilizers are required for bonsai since the soil mix for bonsai is inorganic. A common fertilizer schedule is any 10-10-10 fertilizer during the growing season and 0-5-5 during the winter months.

Bob said wiring is critical for bonsai. Learning how to wire properly is something that everyone must accomplish in order to work on bonsai. Copper wire is normally used with conifers, whereas aluminum wire is used on deciduous trees. Ivan Lukrich, the senior instructor at REBS, assisted in wiring of the demonstration tree. Ivan, who also teaches the beginners workshops, said REBS uses aluminum wire in the beginners’ workshops since it is easier to work with, can be removed and reused if needed.

Ivan proceeded to wire the San Jose juniper. The copper wire will require removal once it begins to indent the branches. The branches will grow larger but the copper wire will not, thus cause wire to cut into the bark making ugly wire cuts. He said observe the wire from time to time and ensure it does not cut into the bark.

Bob estimated the San Jose juniper to be about 20 years old. He recommended repotting with a bonsai soil mix next winter. He would use the same nursery pot but cut the pot in half to accommodate shortening the roots.

When the demonstration was finished, the San Jose juniper was raffled off to the members in attendance. Becky and David Jackson won the demonstration tree.

Bob Shimon, Becky and David Jackson with demo bonsai tree

Demonstration by Bill Castellon – Princess Persimmon

On June 25, 2019, Bill Castellon performed a demonstration on a Princess Persimmon. Bill brought to the monthly meeting and demonstration several personal specimen bonsai of the Princess Persimmon. He also brought several Princess Persimmon trees to work on as demo trees and to be raffled off at the conclusion of his demo. Bill favored the Princess Persimmon for its tiny bright orange to red fruit, small diamond shape leaves and ease of propagation. Bill said the demo species are not readily available nor inexpensive. He said that the species in California were mostly from a group of 2,000 plants imported years ago by Carl Young of Lodi, California.

Princess Persimmon (Diospyros rhombifolia) is dioecious, that is separate male and female plants are required to produce fruit. It is a deciduous tree, originally from China and secondary Japan. It is popular for bonsai due the size of the tree and small fruit.

Bill described his experience and success with propagation of the species by root cuttings. He said root cuttings will produce or replicate that of the parent tree. This is not so with the seeds which can produce variations in the fruit.

The fruit ripen at varying times and so it can be difficult to prepare for a display. The fruit forms on the new growth each year. Pruning can be hard after the fruiting is over. The tree grows quickly. Bill applies fertilizer on a regular basis. He uses Romeo products out of Half Moon Bay, California. He uses the general purpose 15-30-15 fertilizer. Romeo products can be found at a number of retail stores and nurseries in the San Francisco/Bay Area. He feeds fertilizer all summer.

Bill used a bonsai soil mix of Akadama, lava rock and perlite or pumice. His preferred portions are 60% Akadama, 30% lava rock and 10% perlite.

Pests and diseases: Bill recommended three doses of a fungicide for the winter months.

Bill started his demo on the largest of three trees. First, he eliminated one side of a bar branch. He used a sharp knife to clean the wound, a common task for deciduous trees. Cut paste applied over the cleaned wound. He then removed any dead branches and unwanted branches. Aluminum wire was used to wire various branches. The branches can be brittle and so wiring must be carefully wrapped around the branches using both hands; left hand to guide the wire in place and right hand for wrapping the wire around the branch. That is if you are right handed, of course.

Bill described the technique for creating ramification in deciduous trees by allowing some branches to grow outward as long as needed to gain the strength and thickness desired, and then cut back to the secondary branches. Bill kept the demo tree tall and slender with slight movements in the wired branches.

Watering: Bill said he will allow the tree to be on the dry side before watering. Do not let the tree dry out completely.

As with many of the deciduous bonsai, morning sun and afternoon shade seems to work best.

Bill offered the demo female tree with a companion male tree as one of the evening’s raffle prizes. Another female semi-cascade tree was also offered for raffle.

Bill’s Princess Persimmon at GSBF Convention Exhibit 2018
Bill’s Princess Persimmon at Demo June 25, 2019

Demo Princess Persimmon tree.

Oak Styling and Development

There are many ways that oaks adapt to the landscape but the form most associated with oaks that grow on the rolling hillsides and open areas of the landscape is embodied by rounded foliage silhouettes grounded by a buttressing trunk that splits into several vertical and slanting leaders. These trunks, in turn, meander up and around, casting branches every which way to form sub-crowns in the informal umbrella­like shape. Oaks are usually broader than they are tall and are marked with a fountain­like upward and outward branching theme with the tips drooping slightly at the exterior edges.

Unlike pines which are typically styled with defined branches and pads, oak branching takes off more randomly with riotous. Heavy interior branch movement, eventually reducing down to fine twigs at the edges of the silhouette.

The beautiful movement in a mature tree in the landscape is a result of years and years of multiple shoots extending, competing for sun, crowding out weaker shoots, being damaged in windstorms and by insects, wildlife or pathogens. Some just die out and others fill the void in the canopy vacated by those dead shoots and branches.

All of those shoots start out straight. It is the incremental nature of growth over time that yields the wild curves in trunk and branch. In Bonsai, we try to compress those years of movement by wiring those straight shoots with exaggerated curves. When wiring a bonsai branch, the most important section is the first three to five inches. Growth longer than that can be allowed to grow straight to thicken up the interior curves and help them set faster. Bending creates a succession of arcs from which the next shoots will come. This series of arcs, as opposed to straight lines, creates a more natural feel to the tree.

Bonsai Training

As much as possible, working with new shoots yields the best results. They can be manipulated freely without having to fight an old leggy branch with dead patches and aging, reluctant latent buds. Young shoots and branches devote most of their energy to growth and expansion. Older branches lack the same dynamic energy for growth as they must allocate resources to maintain heartwood, sapwood and dead stretches due to shari and jin.

For an oak, the phyllotaxy, or the arrangement of leaves on a shoot, is five to two. This means that between one leaf and the next one in the same position on the shoot there are five intervening leaves rotating twice around the shoot at about 144° between leaves.

Trivia? Yes. When we bend curves in the oak shoot, we can use this growing feature to add randomness to the branch angles and get that meandering oak characteristic.

After allowing the fall growth to mature and store energy in the vascular system of the tree over winter, the tree can be cut back hard in mid-January on both deciduous and evergreen oaks to the point where new shoots are desired. Sometimes, even on an evergreen that means going back to bare wood, leaving no green growth left on the branch. Scary stuff! But forge on! Remember to seal the large cuts with cut paste. To develop branches from scratch on evergreen oaks, try the following procedure.

Year 1. After the above cut back in January, new shoots pop on native oaks at and just behind the cut appearing in late February-early March as the days lengthen and it begins to warm up. New growth is allowed to harden (they become less succulent, turn darker in color and get stiffer, waxier leaves) usually by mid to late April. (Cork oaks are usually about four to five weeks later). New shoots are wired out four to five inches or so in an inclining slope, bending the shoot mostly up and out and up and out, then a little side to side movement in this same section. The shoot tips should be allowed to grow unrestricted for the remainder of the year but remember to remove the wire when it starts biting in, usually in six to eight weeks.

Year 2. Next January cut-back, leaving three to four inches of the new curved branch area. Repeat last year’s process; cut, harden, wire, remove wire, grow. But this time there may be lots of shoots on the three to four inches. Wire three of the shoots (backside, front side, and top) in the same manner as Year 1.

Year 3. Next January, the three secondary shoots from last year are each cut to two to three inches, wired in April after hardening, then choose six shoots (two on each of the three shoots from last year) to wire. Again, remove the wire after the bends are set and, at this time, cut back each of the six shaped shoots to two to three inches. When new shoots come out and harden, wire two shoots and let the branch set in position yielding 12 tertiary shoots. Remove the wire when the bends are set and leave until next January’s cut-back.

Year 4+. From then on refine the branches by cutting back to two to three leaves in January, and each time there-after, as the shoot elongates and before it hardens, leaving a side shoot and leader. Wiring and big cuts won’t be required other than to occasionally adjust the styling or thin over crowded areas. By now, the branch will be well on the path to having that nice ramified oak appearance with good transitional taper.

Defoliation every year or two, can help reduce leaf size after growth hardens, up to about August 1st. Be cautious thereafter. Only defoliate on healthy trees!!

Occasionally, allow a random interior branch to grow outside the canopy without wiring. When it gets past the established silhouette, strip the leaves up to that silhouette and allow it to then run unobstructed. This sacrifice branch will give better transitional taper for the tree where needed, as well as create mature bark, especially with cork oaks. Young, rampant growth is the key to getting good bark. Eliminate the branch when it has accomplished its job and before it weakens the area around it.

We want those interior branches to remain strong because, no matter what we do, the tree will eventually expand and become leggy. Then we need those branches to cut back to and restart the building process. Who said that Bonsai is not perpetual fun?

Ramification maintenance. When the desired branch shape is achieved, pinch back the extending shoots, as they open, at the edges of the branch silhouette. Allow shoots to fully extend if you need to fill a hole in the branch shape.

Deciduous oaks can be cut back in January and thereafter to two to three leaves in May after hardening and maybe once again if it’s extremely strong. Total defoliation of deciduous oaks late in the year (August forward) is very risky and hard on them, using up a lot of the energy reserves of the tree. They can sometimes shut down and wait until the following year to produce new shoots, or throw out a few shoots while cutting off and killing some branches you need. However, after leaf hardening, early defoliation thru June will reduce leaf size and if paired with cutback can generate new shoots as well. If you can’t defoliate, cutting back and thinning the upper section of each branch crown will allow light below, will save interior leaves from dropping and shoots from weakening. Keeping them super healthy and active is important.

Tree Stage

Bonsai Care and Development

Operations and Purpose


Trunk Development Primary Branches

Secondary I Tertiary Branches Twigs and Foliage Maintenance

(Revert back to earlier stage when necessary to solve problems)

Whole Tree

  1. Sun I Temp I Wind – adjust growth cycle – damage control
  • Water – maintain proper hydration
  • Soil I Pot- size and composition / volume and shape
  • Transplant interval – speed-up / slow down growth – refresh
  • Fertilizer- growth regulation – amending for health
  • Pest Control – treat and/or get ahead of Insect and fungus

Targeted Operation

  • Cutting Branches or Leaves Pinching- shorten internodes – maintain shape – bifurcate Pruning – determining shape – bifurcate

Thinning – Open cramped areas – save inner branches

Defoliation – reduce leaf size

  • Wiring – Shape Branch / Design

Dec. 21 Winter Solstice

Mar. 21 Vernal Equinox

June 21 Summer Solstice

Sep. 21 Autumnal Equinox

Angle/ Intensity of Sun Temp

Perform Operations at the Appropriate Times in the Plant’s Growth Cycle

Hormones Auxin · Apical Growth

Cytokinin – Lateral Growth

Pinch/ Prune Hint

“rule” of 2 –Leave 2 buds / leaves – a leader and a side shoot

Wiring Hint

Bend in toward main, then bend out toward sun.

This handout was prepared by John Thompson (2019)

Demonstration by John “JT” Thompson – Cork Bark Oak

Demonstration tree – collected native cork bark oak

On May 28, 2019, John “JT” Thompson performed a demonstration on a cork bark oak (Quercus suber).

There are some 20 native oaks in California. John is experienced in collecting many different types of native oaks. He brought in several species as examples of oak bonsai. He described the general form of native oaks as growing up and outward from the trunk and primary branches.

John discussed oaks’ adapting to their environment. Whether growing in wide open space to hanging by its roots on a hillside. This adaptation makes for ideal bonsai in numerous styles.

First, John examined the base of the trunk and surface roots or nebari. Cork bark was present on the lower trunk. He then evaluated a potential front view, sides and back. The trunk was tapered nicely and movement was present throughout the tree.

John talked about three styling or development methods – cutting back, defoliation and thinning.

Cutting back branches to two leaves and let them grow outward. Wire the first four to five inches and bend in an inclining slope, mostly up and outward, up and outward, then a little side to side movement in the same section. Allow the shoot tips to grow unrestricted for the remainder of the year, but remember to remove the wire when it starts to bite in, usually six to eight weeks later. John said cut back to leaves where you want new shoots to appear.

Defoliate healthy trees only. Defoliation should be done in early May to mid-June. After that is risky to the health of the tree.

Thinning out allows sun light to enter the interior of the tree. Here you are only doing a partial defoliation.

John spent some time talking about working with the younger branches or new shoots on oaks. New shoots can be wired after the leaves have hardened off. Meaning less succulent and stiffer leaf growth. Straight branches need to be wired for creating movement. The most important part of the wired branch is the three to five inches in the first year’s growth. The movement should be up and outward, up and outward, and then side by side, forming curves or arches. Then, let the branch grow out. The next year cut back leaving the bent in the branch. Let new shoots grow out. Select three new shoots, a front, side and back, and allow these to grow and hardened. The steps are repeated to develop ramification in the branches and eventually twigs.

There are growth periods to watch for. Cut back should be done in January. While working with new growth occurs in mid-February to March after the leaves have hardened off.

Cut back longer branches to have a more compact bonsai. Cut back to where you want division. Remove downward growing branches and weak branches. Remove dead branches and twigs from the tree.

John prescribed fertilizers once the tree has hardened off after the early spring growth.

He preferred using aluminum wire over copper wire for wiring branches. John believed copper wire would damage too many latent buds. Whereas aluminum wire was easier to work with on oaks. He said to watch out for the wire cutting or biting into the bark and advised removing the wire after about six to eight weeks.

Repotting – January is the prime time for repotting oaks. Collecting oaks was best done in the spring or fall after a rain. John preferred a deep pot over a shallow pot for oaks. Besides a usual bonsai soil mix, he uses about 12% horticulture charcoal when repotting. He also uses an organic supplement for root growth and development. Dr. Earth has a line of organic supplement products and fertilizer.

Watering – summer watering can bring on fungal issues. It is best to water in the morning versus evening. The soil should be watered, not the foliage.