I have read in many places that we cannot defoliate at all (even partially) the dissected varieties of Acer palmatum because they are weaker than the other A. palmatum varieties. What techniques should be used to ramify those trees and keep short internodes ? Do you defoliate them ?
He is a picture of my Acer palmatum var. dissectum ‘Tamukeyama’ in leaves and the winter silhouette (last winter). This is a nursery tree purchased in 2014 that I slowly developped by pruning once a year in winter (grow and clip) and slightly wire. I plan to eventually make two trees by layering the top section and developping a new apex from the first “Y” fork shy below midway along the trunk,
I have not experience with the dissectums as a bonsai, but I have one potted in a 4-5 gallon planter on the front porch. it is potted in a mix of about 50% potting soil and 50% pumice so the soil is more free draining than dirt (and also much lighter). I am getting some ramification through a combination of cutting/pinching back to the a single pair of leaves/branches and letting it become somewhat root bound. Since these trees have such a low foliage mass I would think that fairly strong fertilization and continuous pinching/pruning back should act like a partial defoliation and encourage ramification.
Do you cut/pinch it in the growing season, and does it respond by a uniform second growth, as if you would partially defoliate another deciduous tree ? Would now be a good time ?
I cut/pinch continuously during the growing as I see the growth extend. I stop this in about mid-August (first frost is in early October) to give the new growth time to harden off before winter. I do the same for most of my maples that are in bonsai pots. I use a pair of 6" bent nose tweezers to nip off the second set of leaves as they start to form on the bonsai - sometimes I catch them and sometimes I don’t. I will try to remember to put the front porch dissectums on the same check schedule which recently has been when i need to take a break from the computer as I work from home!
@MartyWeiser, when you cut the shoots to the first pair, does it initiate systematically another flush of growth, or do you see sometimes that the branch sits there and does not produce another flush of leaves ?
I seem to recall it is a mix of new shoots at the last terminal, new shoots back further, and just sits there. I have not taken a systematic approach to this patio tree in the past so I have not paid that much attention to the response. I plan to do so this year.
