Every season in bonsai brings something enjoyable. Seasons also bring unique threats that we should understand and prepare to prevent...note the difference between preparation and reaction. . Activities geared toward putting trees down for the winter successfully are essential for a good growing season next year and an enjoyable Autumn. Activities associated with winter should begin in about September... at least for me in Indy. So, here are a few fall color shots of a nice root over rock Japanese Maple along with my fall fungicide/winter prep regimen complete with some whys and wherefores.
1) Fungicide: Of course I am spraying monthly during the growing season but fall is particularly cool and wet creating a great opportunity for fungus to take hold and weaken trees. Some fungi will not emerge as an obvious threat until spring when it wakes up. Juniper tip blights such as phomopsis or kabatina are good examples (copper is great but mancozeb is best). Starting in mid September lasting though mid November I use a weekly application alternating between Daconil & Liquid Copper. Using a 1.5 gallon pump sprayer I add 3 TBSP of either..not both. I prefer to spray late in the day to avoid any sunburn. Both chemicals need about 4 hours to dry. So, check your weather. And yes that is like EIGHT 6-8 applications of fungicide. I am not a fan of a preventive systemic. If something slips past my nuclear arsenal I will use propaconozol most of the time.
My last fungicide spray is with Lime sulfur/Copper mix. This is the Bordeaux mix. I do this when I am bringing trees in for the winter....a final time usually around Thanksgiving.
Spray the outer canopy, but do not forget to spray inside the canopy and direct your nozzle upwards to the underside of branches.
2) Fertilizing. Continue to fertilize. I use alfalfa tea with seaweed and fish which are relatively well balanced overall. I have not read anything yet that compells me to switch to 0-10-10 for my trees in autumn. Keep it simple.
3) Clean your overwintering area. For some its outdoors, for others an unheated garage. Either way clean it. This means getting leaves, debris and any insects out of the way. Spray the area with copper & malthion...I winter in a garage and do use a mild insecticide in the nooks and crannies. I also wipe down overwintering tables.
4) Clean your trees. Remove all the leaves from deciduous trees and any old fertilizer cakes from everything. I use a toothbrush and soapy water with a little vinegar to clean the trunks of my deciduous trees.
5) Make your check list. Is there room for your trees? Can they be accessible to you? Is the cover for your winter home in good condition? Do heaters work? If you winter in a garage, do you have good ventilation? This is essential for keeping trees dormant and fungal diseases at bay. More on that later.
So, that's it.
