Tree Tips
November 2024
Congratulations, everyone!
What a great show we had this year! Thank you all for your hard work in putting it together. Every aspect came together seamlessly, from set-up to tear-down, both in record time. It’s amazing what wonderful trees our members have worked on and shared with us. Bravo!
I hope everyone had a chance to visit the Pacific Bonsai Expo in Oakland a week after our show. It was the best display of bonsai I have seen in this country over my forty-some-odd years of practicing bonsai—absolutely spectacular! They will have another expo in two years, so if you have a tree you would like to show, you can submit it for consideration in Spring 2026. A worthy goal for us all!
Seasonal Care Tips for Bonsai
Now, back to bonsai. It actually seems like fall is here, with cooler days and nights. Growth is slowing down—there's even a little color in my Boston ivy.
Each year, I save a lot of water from my downspout diverter off the roof. I store it in 32-gallon trash cans to use later next year after the rains stop. It’s clean water that I can use to hand-water specific trees with a 2-gallon can. I also have a water pump in a 50-gallon can attached to a hose to make general watering easier. This is better than San Jose Water from the tap at this time of year.
It’s time to style, wire, pluck needles, and make big bends on conifers. You can work on practically everything now except black pines (wait until next month). Here in the Bay Area, continue to fertilize your trees with low-power fish emulsion (5-1-1). This will promote a good energetic spring response in a few months. As the leaves fall after changing color on deciduous trees, you can cut back to two buds from December to mid-January to set up growth for spring.
The growth that has been coming on since summer should be hardening and will no longer snap like a bean if you bend it. But try this: exercise the branch before you bend it in one direction. By this, I mean pre-bend it using the fleshy part of your fingers and palm to support and twist the branch in the direction you wish to ultimately bend it (not back and forth!) before actually applying the wire. Trust your fingers to tell you if you have gone far enough; they are more reliable than your eyes. You can achieve much more acute bends this way. If it still resists, you may need to use raffia to support it. Spray the bent branches with an anti-transpirant like Anti-Stress 2000®, Cloud Cover®, or Wilt-Pruf®. This is an ideal time to shape those branches before they harden completely over winter.
Preparing for Winter
Deciduous trees should be wired when most of the foliage has fallen off but before they become brittle later in the winter dormancy period. Remove the foliage when about 75% has turned color. If you wait until December, any cutting may cause some trees to bleed excessively.
You can still style those junipers and even transplant early flowering trees like quince, but do protect them from frost if we get cold weather.
For most trees, now is the time to clean off the top layer of sphagnum moss we had on during the hot summer season, as well as the topsoil that has accumulated spent fertilizer and weed seeds. Make sure it doesn’t get up into the bark of your trees. Silver moss used for the show can be taken off and placed in your landscaping where it will get morning sun and regular water. You can grow a new crop for next year. Clean off dead leaves and remove weeds, and add some super phosphate to the topsoil during any transplanting.
Be sure to clean out the foliage in the crotch areas to allow sunlight into the interior, stimulating new buds and exposing pests.
December is usually the best time, but if the pine needles have hardened, clean out the old needles on your trees to let sunlight in. Leave more needles on the bottom branches (10 to 15 pairs) and 7 to 10 on top. At this point, we want to encourage as much sunlight as we can. Later, we’ll thin out even more, but watch that you don’t damage tender needles that haven’t hardened. Use tweezers or scissors if plucking causes bleeding. Days are getting shorter and cooler.
Remember to make your first application of dormant spray at Thanksgiving. Ultrafine® oil, Neem oil, copper, and lime sulfur sprays work well. Do not mix them together!
Water your trees when they need it. This means waiting until the upper soil has dried and is lighter in color before watering. Then water thoroughly. Don’t keep them too wet, and remember that as their growth slows, they use less water. If too much water accumulates in the pot, tip the pot up on one side with a block to help drainage.
Whatever shade cloth you had for your trees can be removed at this point. The hours of sunlight and the angle of the sun are approaching their minimums, so the trees need all the light they can get. Additionally, protect tropicals as temperatures drop below 45º. 🌳
