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Club News – April 2020

Oaks for Bonsai with Michael Greenstein
April 17 @ 7pm via Zoom

Michael Greenstein will give a remote, “shelter-in-place,” virtual presentation on “Oaks for Bonsai” as other members watch online. This meeting is an experiment and so only club members are allowed to attend. Michael sent email to everyone about how to join. If you didn’t get this information contact our president, Richard Phillips.

Michael has practiced bonsai since 1969, and studied with Tosh Saburomaru, John Naka, and Kathy Shaner. He has cultivated oaks since 1988, when Tosh said to Michael, “grow an oak bonsai, and grow old with it,” as he handed Michael a two-year-old cork oak seedling. He is a self-described Oak bonsai enthusiast, but does not consider himself to be an expert. He continues to practice with enthusiasm. 

In the talk, Michael will cover the organization of the oak family, some oak fun (and obscure) oak facts, and characteristics of several oaks suitable for bonsai. He will then give a virtual tour of some of his oak bonsai and encourage others to show images of their oak bonsai


60th Annual Show Canceled

We’re sorry to announce that our 60th Annual Show has been canceled. 
The safety of our members and the public is far more important. We’ll be back next year!

However, our Show Chair has put together a video that showcases our Legacy Trees – trees that were owned by our founding members or those that have been in our club for a long time.


Message from Our Club President

By Richard Phillips

I want to give everyone an update on what the Kusamura Board of Directors, officers and committee chairs are doing as we adjust to the crisis that has forced an indefinite halt to our planned meetings and other events.

Sadly, this crisis has hit us when we were planning our 60th consecutive annual bonsai exhibit – an achievement we were all looking forward to celebrating as a club. That exhibit has been canceled and most likely will not take place at all in 2020.

However, we are developing an alternative, which while it doesn’t offer the kind of camaraderie of setting up and running the show, will give us the opportunity to share our love of bonsai with each other and with the public. In fact, it will allow us to reach an audience that potentially includes the whole world.

Using the deep technical and artistic resources of various club members, we are planning a virtual exhibit of our bonsai. The initial phase of this will be a photographic “essay” of heritage trees – those trees that have a long association with the club. Many members have trees in this category along with their history. Charlene Fischer is leading the effort to collect images of these trees along with their stories. These will be put into a video format for posting on our existing YouTube channel.  If you’ve never seen it, simply Google “Kusamura Bonsai YouTube” and you should get the link. There are three videos currently on the channel, thanks to Dave Curbow.

A second initiative we have started is to hold monthly meetings online using video conferencing software. Our first meeting will be on April 17th and will feature our own Michael Greenstein on oaks. Michael has his presentation ready and we will send out the details of how to tune in very soon.  The May meeting will feature the debut of our show video on heritage trees and possibly other content. Other meeting topics will be forthcoming.

We will continue to explore ways to share our bonsai journeys with each other as we take the necessary steps to ensure the safety of our communities and ourselves. As maddening as technology can sometimes be, it also gives us the tools to feel connected even though we must remain physically separated. Watch your email for invitations to join these opportunities as they are created.

As always, your feedback, insights and suggestions are welcomed, now more than ever.

Monthly Tasks

Each month there are a number of tasks you need to do to your bonsai – from repotting, to fertilizing to spraying for pests. We have put together a checklist, customized for the San Francisco Bay Area to help you. This checklist is adapted from earlier work by Mitsuo Umehara. 

This month: April Tasks

Fertilizer Changes

Normally the weather is warm enough that time-release fertilizer such as Osmocote will begin releasing fertilizer. But it’s been cooler than 70 degrees most of March and April so you may want to supplement any time-release fertilizer with liquid fertilizer such as Miracle-Gro. Just make sure you dilute it more than the directions on the package say. For more details about fertilizer refer to Fertilizer Basics.


Wisteria Bonsai

By Rita Curbow

While Chinese wisteria and Japanese wisteria are styled as bonsai, the Chinese wisteria is more commonly used in the United States. Determining what type of wisteria you have is as simple as counting the leaflets on a single stem.

Chinese wisteria will have 7-13 leaflets while Japanese wisteria will have 13-19 leaflets on a stem. The length of the flowers is different also along with when the flowers will appear. The flowers of a Chinese wisteria open simultaneously, appear before leaflets appear, and their racemes are 7 – 14” in length. The flowers of a Japanese wisteria open from top-to-bottom, appear after the leaflets appear, and their racemes are 8 – 64” in length.

Chinese Wisteria (left) vs Japanese Wisteria (right) (Illustration courtesy of William Valavanis)
Chinese Wisteria (left) vs Japanese Wisteria (right) (Illustration courtesy of William Valavanis)

When you train a wisteria bonsai for show, the focus is on the flowers of course. Most wisteria used for bonsai have purple flowers versus the white and pink which have an inferior appearance. Use tweezers to remove withered flowers. Remove a raceme when 70-80% of the flowers have bloomed. Not doing so will result in fewer flowers the following year.

Photo courtesy of Christine Weigen
Photo courtesy of Christine Weigen

When you train a wisteria bonsai for show, the focus is on the flowers of course. Most wisteria used for bonsai have purple flowers versus the white and pink which have an inferior appearance. Use tweezers to remove withered flowers. Remove a raceme when 70-80% of the flowers have bloomed. Not doing so will result in fewer flowers the following year.

When first developing a wisteria as a bonsai, you will want to focus on encouraging vigorous growth and branch development. Transplant them every year or every other year, fertilize and water them sufficiently, and allow the vines to extend and the roots to develop at this stage of vigorous growth. Prune the tree two or three times a year, each time cutting back to two or three nodes. During this time of frequent repotting and allowing robust growth, you will not get flowers. Once you have the desired shape, then you will focus on promoting flowers.

Root restriction promotes flowers on wisteria and slows down the growth of foliage. Wisteria flowers will not bloom until the fine roots form a mass and begin to circle the bottom of the pot. After the spring flowering season, put the wisteria in a container of water that will keep the bottom one quarter (1/4) or one fifth (1/5) of the roots wet at all times. Do this until the autumn equinox. Soaking the roots in this manner will cause them to suffocate but not rot. If fertilized properly during this time, you will get lots of flower buds for the following year and little foliage growth which is what you want at this stage for your wisteria bonsai. When fertilizing, apply to both the container of water and the top of the soil.

Sometimes you will want to do leaf thinning to allow light into the interior of your tree. Buds in the shade will become vegetative vs. flowering buds. When you leaf thin you will encourage new growth thus requiring more leaf thinning. If leaves are yellow or appear unhealthy, you need to apply more fertilizer. Wiring can be done in winter or summer.


Pruning Fruiting Bonsai such as Crabapple and Quince

In addition to preventing disease or pests, you want to prune flower and fruiting trees at the appropriate time to enable flower and fruit production. Heavy pruning should be done in the fall after the leaves have fallen off while lighter pruning can be done in the spring under certain conditions. Note that large leaf removal should be done throughout the year to allow more sunshine into the interior of a tree.

Branch pruning can be done starting in the spring and as long as nighttime temperatures stay below 60 degrees. After that you run the risk of getting nematodes if you prune. What are nematodes you might ask? Nematodes are microscopic worm like creatures that play a significant role in influencing C02 emissions from soil and play a key role in the food chain but they are not desirable for bonsai. Some nematodes eat roots of plants while others prefer the plant material itself. You will know that your tree has nematodes when you see black spots on the branches or stems. Do the black spots signify that nematodes are attacking the plant in each of those locations? Is the dark spot the reaction in the plant to the secretions discharged by the nematode? I did read online that a foliar nematode forces enzymes through its’ stylet (a needle-like, spear mouth part) into the cell where cell components are digested and then drawn back into the nematode’s digestive system through its’ stylet. I am assuming those are the black spots. You cannot get rid of the black spots and the nematodes once your bonsai has them. You will probably opt to toss the affected tree.

Flower buds on fruit trees such as crabapple and quince will form on the terminal bud or buds below the terminal on the short branches of your tree. Rarely will flower buds develop on long healthy growing branches.

In the fall, the crown of the tree and other vigorous areas of the tree should be pruned more severely than lower branches on the trunk and slower growing areas. Prune twigs that have become too crowded, have grown too long or have long internodes. Fall is also when you would transplant a crabapple or quince if needed. 

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