Shishigashira var. airlayer question

I have a few pretty large shishigashira var. Japanese maples. They are grafted of course. But, there are many nice branches in excess of 1 inch diameter with nice secondary branching.

So, I've airlayered many trident maples, and other species very successfully & know how to do the work. Yet, the same process has not yielded great success with the shishigashira's. (Cut & Peel bark, scrape cambium, apply hormone, apply sphagnum & plastic wrap).

Can someone with PRACTICAL knowledge (first hand experience) with propagating this variety let e know what I maybe missing.

I've also heard to let the cambium layer & cut dry out 1 day before wrapping it up.


Thanks!

Can someone with PRACTICAL knowledge (first hand experience) with propagating this variety let e know what I maybe missing.

I know, I know, I have NO experience with this CULTIVAR. However, Acer palmatum is Acer palmatum, and I have layered several other cultivars of the species and it took nothing special in terms of procedures.

I assume you started the layer in early spring, used rooting hormone, and kept the moss moist but not soggy, and kept the layer intact through the entire summer without poking inside it looking for roots.

How many have you tried?

Hi Neil
Twice I worked on air-layer Shishigashira. The roots have developed well enough. Unfortunately, after two growing seasons was a dead tree. The same was repeated at the Acer p. disectum and disectum Garnet. I heard that some maple cultivars not grow on their own roots. I think it's a given genetic basis.
Gretings Pavel

Neil, while I haven't layered shishigashira, I root them regularly without difficulty. They have grown well on their own roots with a well aerated soil. Generally, if they root from cuttings, root systems are usually ok. Shishigashira are slow developing either grafted or on their own roots.
Wood

First of all, an acer palmatum is not just and acer palmatum. However, there is a generic acer palmatum that is commonly used as the root stock for the more exotic varieties. In all my air-layering attempts I've used the standard hormone powder that one can find at home depot. I am guessing it is 8000 ppm (0.8%) IBA, and that may be the problem.

The generic acer palmatum is so easy to air layer that it makes one feel like a genius. The variety 'Orange Dream' is nearly as easy. On the other hand, I have attempted about 6 air layers of 'Shinde Sojo', but lost them all in the course of their first potted winter for reasons that are not entirely clear to me. I tried 'Higasayama', but all failed to produce roots and died on the tree (appearances suggested that it was maybe because I kept the sphagnum too wet). I tried air layers of 'Aka Sigatatsu Sawa' that didn't produce anything in the first year but were left on the tree over the winter. One layer/branch died on the tree after leafing out the following (this past) spring. The other is still alive but has yet to produce any roots. I tried to air layer 'Shishigashira' and 'Okushimo' varieties in the spring of 2011 but no roots were produced, but the moss and bags remain in place.

Through a lot of digging I've found that 1% to 2% IBA talcs seem to be recommended by horticultural research for japanese maples (and most specie air-layers, for that matter). So I will be ordering 2% rooting powerder on-line in the next month or two and applying it to the overwintered air layers once these trees have leafed out this coming spring. Then I will spend the summer looking for roots!

Bottom line, though, is that you have company but no answers (yet?).

GaryWood wrote:Neil, while I haven't layered shishigashira, I root them regularly without difficulty. Wood

Wood,
What technique and timing are you using with your cuttings? Are you using softwood or hardwood cuttings.

Thanks

Frank, early summer cuttings after the shoots are starting to lignify. DIP-N-GROW @10:1, 90% pumice 10% peat under mist.
Wood

In terms of timing of making the air layer, ive heard different opinions now. Is it best to do as soon as buds swell, as soon as leaves open, as soon as leaves harden? Any opinions on moss vs soil as a rooting medium for the airlayer?

bucknbonsai,

The conventional wisdom is to wait until after the leaves have hardened, however, the timing likely isn't important.

The 'mechanics' of trees are that stuff going up goes thru the xylem that is left in place when you make an air-layer. Auxins (that stimulate root growth) and carbohydrates made by the leaves go downward in the cambium that you remove. So the tree should be able to supply what the branch needs to stay alive, regardless of when you ring the branch. However, there is no chance of developing any roots until the leaves are out - no carbs to move down feeding the formation of roots, even if we've dusted the cambium discontinuity with auxin (as IBA or some similar rooting hormone).