There are lots of methods to take cuttings for bonsai, this is the one that I have had the most success with. Equipment For cuttings: I use a 100 watt Metal Halide Light source, I have also had equal success with fluorescents.
For bottom heat I am using a Hydrofarm heat mat with thermostat. The thermostat will be set at 75 degrees, which is especially useful for Japanese Maples.
Pots and Soil: For the container I will be using a 1/2 size flat with a 36 cell pack. The soil will be an equal mix of peat and perlite. This is a light mix which will help with early root development and prevent fungal attack.
For these cuttings I will use Hormex 16 and Hormex 30 for the lace leaf maples. Hormex works great for trees and shrubs because it can be bought with much higher % IBA (indolebutyric acid the root hormone). For example most regular rooting hormones have something like a .1% IBA, whereas Hormex 16 has 1.6% IBA. Stronger doesn't necessarily mean better though. Using too strong a concentration will end in necrosis on the cutting. I have found it to be safe in the past to use Hormex 16 on most of these cuttings. The notoriously hard to root lace leaf maples respond better to Hormex 30.
The species I will be dealing with today are: Acer ginnala, Acer palmatum 'Viridis', Acer palmatum 'Crimson Queen', Acer palmatum 'Butterfly', Carpinus turczaninovii and Carpinus coreana. The Viridis is the green lace leaf Japanese maple and the Crimson Queen is the red lace leaf maple. I didn't get any good pictures of the Butterfly Japanese maple leaf, but it is absolutely gorgeous. They have small green leaves with white and pink edges.
The three Japanese maple cultivars came from trees of friends. To get them home, I immediately wrapped them in damp paper towels and sealed them in a Ziploc bag. When I got home, I washed them thoroughly to remove any bugs that may have made the journey. I then placed them in a cup filled with water. You need to make sure to never let your cuttings go dry. The faster you can go from plant to hormone to soil, the better (not the case with Jades).
I like to make my cuts near the internodes (some plants will only root from here, others it doesn't matter), and remove the bottom two or three sets of leaves. I like to have 2-3 sets of leaves on a cutting. If the cut is not fresh, as in the case of the maples, I make another cut and immediately dip in hormone. I then put the cutting into a cell, where I have already punched out a small hole with a chopstick. Just place the cutting in the hole and firm the soil around it. The soil should be moist, but not dripping wet.
When all the cuttings are in place I mist the whole tray once again, and place the humidity dome over the tray. The humidity dome is key, as it maintains a 100% level of humidity around the cuttings. This prevents the cuttings from losing water to transpiration, which causes wilting. All of this gives the cuttings a stress free environment in which they can establish roots.
After securing the humidity dome, I place the cuttings on the heat mat set at 75 and underneath the light. The bottom heat helps encourage new roots to grow. It will be 4-6 weeks before most of these cuttings have grown a strong enough root system to transplant, possibly a few more weeks for the Japanese Maples.
