Now is a good time to be repotting your bonsai. Repotting, styling, wiring, trimming etc. can all be accomplished from now until mid March ish, depending on the weather. Check for bugs, funguses, and any other nasty things that might have climbed onto your bonsai during the fall. We are still having a very dry winter so make sure your bonsai are watered so that they don’t dry out. The strong winds that occasionally blow up the canyons dry out our trees really fast.
Make sure all of your tools are clean and sharp. Prepare all your needed transplanting/repotting supplies prior to beginning. We find that we make a lot more efficient progress when we plan a day or two ahead of time, get the bonsai or stock material all lined up and then go to work on them and spend at least a full day. Applying the force required to do this work is best done in a steady and consistent way. Use Superthrive, B-1, or some other rooting stimulant product. Do not fertilize the repotted bonsai until they have begun active growth again; this should be sometime in April/May.
For gathered material from the mountains you can put a little bit of Horminex 1, 2, or 3 into the pot and water as you normally would. In the middle of April treat all gathered material with Merit or some other ‘systemic’ fungicide, bug killer, fertilizer mix. Most of the pines and many junipers that we gather in the mountains have borers living in them and the use of the systemic product will kill them after 3-5 applications before they begin the move around in your garden.
This is one of the busiest times of the year for those of us who grow and care for bonsai. The sun is lowering in the southern sky, the days are very short, the temperature is getting colder and things are generally wet. When this is combined with the wind and the conditions affecting your bonsai the care regime becomes increasingly complex. Here are a couple of hints:
Begin by looking closely at each bonsai and removing all of the spent leaves. See if you have scale insects living on your bonsai; they may seem dry and pop off pretty easily but they are overwintering and need to be removed. Check for biting wires if you have placed wire to style in the time frame from August till now. Check to see how fast your pot is draining. If it is slow mark the tree to be repotted this winter or early spring. Because we have so many trees we have begun our repotting already and will continue to do this until early April of next year.
Move your material into full sun, such as it is. Place a small object under one side of the pot so that it is tilted slightly; this will let the rainwater run off more quickly. Prepare all of your repotting materials (soil, wire, screen, work area, place to put old soil, ground pruners and branch pruners) and make sure all your tools are sharp and clean.
Black Pines can be cleaned up and styled from now on but should not be repotted until next spring when it begins to warm up. If you have White Pines they can be repotted from late December well into next spring. Junipers can be repotted once the days begin to warm up, usually March/April. Although it is not uncommon for us to experience a nice and warm week or two in December. Look closely at your Junipers if they seem to be getting a grey or washed out looking. This can often be a result of mites. Treat with oil and a systemic pesticide. Pines and Junipers can be lightly pruned (cutting of small branches and shoots) and wired from now on. Do not make large cuts until Spring because major open wounds invite bad things to crawl into your bonsai. Make sure that if you need to make larger cuts (1/4″-3/8″ branch) that they are very clean and sealed up good with cut paste or latex paint.
This is the time of year when we travel to the mountains to gather trees. It is also a good time to think about plans to repot your bonsai, cut them back, place styling wire, feed with 0-10-10. Leaves should be turning into fall color. Some will be brown and crisp while many will be turning red or gold. Move your trees to spaces where they get more sun.
Make sure you mark your calendar to spray with dormant oil in December and then again in January. This will stop most fungus and a lot of the small bugs that will want to attack your bonsai in the Spring. See you at the GSBF Convention in Sacramento!
Now is a good time to begin feeding gently with 0-10-10 (phosphorus and potassium) to strengthen root and lower trunk to provide for a good start next spring. Keep an eye out for woolly aphids, spider mites, scale and spittle bugs. They are all active at this time of year. If you find them try physical systems first (spray with hose, scrape off with hands or toothbrush, use a damp cloth) and then follow up with oil. Don’t put oil on any plant that will get the sun that day. Apply in the evening and avoid the leaves because the oil will burn them. Check the wires you applied in Spring and Summer (after defoliation). Your trees are actually beginning to put on a spurt of growth and the wires will bite really fast. Check the speed of drainage in your pots. Any bonsai that have slowly draining pots need to be repotted. Mark them with something you can find really easy so when the leaves are gone you can begin repotting without have to search around your collection.
We stopped feeding our bonsai about 3 weeks ago. Toward the end of September we will treat them all with 0-10-10 to help them get ready for winter. The last month has been used to defoliate Japanese Maples, trim the big Chinese Elms, work on all the different trees that are growing here.
This time of year is the “Dog Days”, it is so hot that going outside for an hour can be a real effort. Drink lots of water and make sure your bonsai are given plenty of water also. The Maples that we defoliated three weeks ago are making such nice small (and green) leaves to replace the ratty brown ones that were just hanging on. Not many pests this time of year for us
We have experienced the very hot (100 degrees and above during the day with nighttime lows of about 75 degrees) weather of our typical July/August days. Some of the trees are suffering and some are happy about the heat. Maples, Elms, Crabapples, Oaks, Beeches and some Boxwoods will have brown leaves or the leaf margins will be burnt. Not to worry. Look for the emergence of small green buds below the damaged tissue and you will see them coming out behind the ones that are dead. Some bonsai people call this process defoliation without scissors.
On the other hand Pines, Junipers, Holly, Ficus and Pyracantha are quite happy as the heat gets hotter. The hot days and nights seem to agree with their individual needs and they tend to grow most when our deciduous trees are basically stopped. Just remember to water well. Take off the crispy leaves and the bonsai will look niceras the new leaves emerge.
Our president Paul has provided a lot of good information regarding summer care. I would like to offer a few more tips/observations that might help.
1). On a hot afternoon, say 103 at 4pm; if your clay pot is sitting in the sun the external temperature of the pot can be over 120 degrees and the inside of the pot above 130 degrees. This heated clay is right next to the most tender shoots that are feeding your bonsai. These feeder roots are killed by the high heat and although the tree is getting plenty of water it is still fading away. When those root tips (they are the white or cream colored part right at the very end of the root) die or are damaged it does not matter how much water you put into the pot it aint going to get into the tree.
Here are some suggestions:
Obviously the best solution if it is possible is to move your bonsai into an area with afternoon shade. – Get some material from a swamp cooler (it looks like a big sponge) and cut it out to fit over the pot and will reduce the temperature. – Wrap the pot up (don’t plug up the drainage holes) with an old rag or towel and it will help a lot. – Some people put ice cubes on their bonsai soil in the hot afternoons. I have not done this but heard that it works ok.
2). The EID is requiring me to reduce my water consumption by 30%, so while I continue to water the bonsai every day I have started watering the stock plants every other day. Many of them are wilting or dying from lack of water. My plan has always been to place the trees into a fast draining material and water frequently. Now that I can no longer do that I am going to have to plant my stock trees into a denser material with more organic matter, and Akadama, in it to retain the water longer.
3). For our smaller bonsai we have placed them into/upon large (20″x30″) bakers trays with Hyuga, or other fired clay, about 1″ deep on the bottom. The little bonsai sit in this wet rock most of the day and they seem to do quite well. It is not uncommon for us to lift up one of the little pots and find roots 18″ long growing out of the drainage holes and through the gravel.
Finally, each of us is faced with cultural problems that are unique to our own bonsai collection. Is the property flat or sloping? do you face east or west? are there big trees where you keep your bonsai? how do you water? what fertilizer do you use? how big is the pot in relation to the tree? and on and on.
The proper care and maintenance of bonsai is a lifetime learning adventure. Enjoy and see you soon