Necrosis
Seedling
I've been bitten by the propagation bug. I realize that Maples are easier to propagate via air layering or grafting. However, after my complete and utter failure last year, I am compelled to solve this riddle. There are some good resources on this site, youtube, and other bonsai educational sites. However, I have yet to see a compiled source of information which is what I will attempt to do here. In addition, I'm performing a small experiment to determine which rooting medium is best.
So, in summary:
There are 2 ways to propagate Maple cuttings. You can propagate using semihard wood (this year's growth) after it has hardened off during the spring. This takes place approximately 6 weeks after the appearance of new foliage. You can also propagate via hardwood cuttings (1-year growth) before buds push during the spring.
The method cited by several people recommends taking cuttings that have at least 4 nodes (roughly 6 inches). The ends should be cut with a sharp knife to expose the cambium. Rooting hormone composed of the active ingredient IBA should be placed on the ends. There are several brands and types of IBA you can use. Be sure you are looking at the percent concentration of IBA. Hardwood cuttings require higher doses of IBA (somewhere between 0.1% and 0.3%). Be sure to note the concentration of IBA as some suspensions are unreasonably low (i.e. 0.00004%). Plant in soil medium. The options here are large. The most commonly cited soil types include perlite, sand, akadama, and sphagnum moss. I'm sure there are others but I will be sticking to these 3-4 in this experiment. It is recommended that the cuttings are placed into the soil covering at least 2 nodes. Place them into a plastic container with some sort of clear lid or plastic wrap. Water them once. The water initially placed in the container will help to keep the plant turgid until the plant can produce roots to allow for transpiration which can take anywhere from 2-6 weeks. Do not overwater as this can cause rot and promotion of pathogen. The container should be humid. Propagation resources commonly cite 80-90% humidity. I suppose if you are getting the formation of water droplets on the lid you are likely headed in the right direction. Keep out of direct sunlight but allow some indirect sunlight. Keep cuttings about 70F. The use of a bottom warmer 10 degrees above the ambient temperature will encourage the formation of roots as well.
So, in summary:
There are 2 ways to propagate Maple cuttings. You can propagate using semihard wood (this year's growth) after it has hardened off during the spring. This takes place approximately 6 weeks after the appearance of new foliage. You can also propagate via hardwood cuttings (1-year growth) before buds push during the spring.
The method cited by several people recommends taking cuttings that have at least 4 nodes (roughly 6 inches). The ends should be cut with a sharp knife to expose the cambium. Rooting hormone composed of the active ingredient IBA should be placed on the ends. There are several brands and types of IBA you can use. Be sure you are looking at the percent concentration of IBA. Hardwood cuttings require higher doses of IBA (somewhere between 0.1% and 0.3%). Be sure to note the concentration of IBA as some suspensions are unreasonably low (i.e. 0.00004%). Plant in soil medium. The options here are large. The most commonly cited soil types include perlite, sand, akadama, and sphagnum moss. I'm sure there are others but I will be sticking to these 3-4 in this experiment. It is recommended that the cuttings are placed into the soil covering at least 2 nodes. Place them into a plastic container with some sort of clear lid or plastic wrap. Water them once. The water initially placed in the container will help to keep the plant turgid until the plant can produce roots to allow for transpiration which can take anywhere from 2-6 weeks. Do not overwater as this can cause rot and promotion of pathogen. The container should be humid. Propagation resources commonly cite 80-90% humidity. I suppose if you are getting the formation of water droplets on the lid you are likely headed in the right direction. Keep out of direct sunlight but allow some indirect sunlight. Keep cuttings about 70F. The use of a bottom warmer 10 degrees above the ambient temperature will encourage the formation of roots as well.