Please share your advice on caring for slow-rooting airlayers.

I airlayered some trees this year, made the layers at the end of May through the first week in June. I have three layers on a tall gingko, three on a styrax, one on a plum and some layers on Japanese maples: Osakazuki and Ukigumo.
I checked the progress today and discovered very few roots growing. I have never over Wintered airlayered trees and would like some advice on how to protect the layers. I am hoping that they can be insulated somehow. I know they will freeze, but is this all right? Has anyone had success letting their airlayers freeze ... with them resuming growth the next year? Thank you for your thoughts and suggestions! Salut, Todd

Gingko

Styrax

Plum and Ukigumo Maple

I would reccomend putting them in the garage for winter to help keep them from freezing.Ginkos are bad about roots bursting from being frozen they have a LOT of water retention in their roots so they need to be kept from freezing or it may end up killing the tree/layers.

Moving them to the garage or other protected, but unheated, area would be best.

Have you gotten roots on all of your layers? In my experience, layers on Prunus sp. fail as often as they take.

There seem to be quite a few on the Prunus. I may be able to cut it off next month.

I would advise against air layering one above the other, as you have on the Ginko at least, it often leads to failure. There is a sound horticultural reason for this, but having been out at an 80th bithday party all day, I'm probably not the best person to fill in all the details.

There is still time for sufficient roots to form. Keep them in a sunny spot and make sure they don't dry out. If they are still insufficiently rooted by the end of October, protect them with a couple of layers of bubble wrap and they should be fine. You may need to recut the cambium if it has formed a bridge over the gap by next spring.

Seth Ellwood wrote:I would reccomend putting them in the garage for winter to help keep them from freezing.Ginkos are bad about roots bursting from being frozen they have a LOT of water retention in their roots so they need to be kept from freezing or it may end up killing the tree/layers.

That's what happened to the only ginkgo layer I've done: in the spring, I discovered that the roots had formed, but were rotten. Yet, the base of the layer was swollen, so I cut the rotten roots to the living tissues, planted it in a growing mix and put it in my garage. Several weeks later, no leaves had formed, I removed the layer and saw it didn't form new roots.

I then put it in my garden, thinking there's one chance out of a million that what was now more a cutting than a layer would take... And it did!

Here are pics when I removed the layer (and was very disappointed) :



After cutting the rotten roots:



No photo of the new tree in the ground, and it's raining cats and dogs at the moment, but the tree is very healthy.

Alain, what time of year did you do this? Sounds like something I might try if no more roots form. Blessed rain!
Salut, Todd

... and this thread is a good example of what Iris advised in another thread: knowing the basic mechanisms of plants helps!

Have a look at this page, and Will's comment will seem even more evident on why putting several air-layers on the same trunk or branch are quite likely to fail:


Sap circulation

Todd Ellis wrote: Alain, what time of year did you do this? Sounds like something I might try if no more roots form. Blessed rain!
Salut, Todd

I removed the "layer" in early March 2009, and planted it in the ground at the end of the same month/beginning of April.

About ginkgo cuttings: people told me they were fairly easy to make, in late winter under a protected frame. Tried it two years with about 10 cuttings each time, none of them took

I've never tried it with ginkgo, but with species that can have an important growth in a season (deciduous trees mainly), putting a tight ring of wire where you want to air-layer the next year gives good results : the bark makes a swelling, so when you cut a ring of bark, there are more cells from which roots can grow. I tried it on maples, especially with a trident maple. But it's true that even without that, maples are fairly easy to air-layer anyway