Failed Crabapple Air Layer

[W3rk]

I have a nice full grown/mature crabapple in my back yard. Early this spring after it had leafed out I started an air layer on a decent branch (easily 3 months ago now). I pretty much did everything by the book and I think as well as I could have - including using the "disc" that Sorce recommends for root spread. I kept tabs on it made sure it didn't dry out. I"m also certain I cut to a good/correct depth because the leaves and branches above the cut remained healthy for a long time.

Over time I noticed some smaller branches that died back, but that's not uncommon on this tree. Then all of the leaves on this branch - above and below the cut - started to brown and die. So this weekend I went in and opened it up. At this point I was certain that it was a lost cause with all of the dead leaves. Here's what I found. Lots of growth but lots and lots of little nubs that never really developed into roots. Kind of neat, but a bummer that it failed:

 

[Dan92119]

If it were mine I would cut it off the tree, cut it so it maybe 6 to 8in tall and stick in a pot. I have heard crab apples air layer pretty easy.

I had a mulberry air layer that looked like that. Put it in the ground and it took off like crazy.

 

[W3rk]

If it were mine I would cut it off the tree, cut it so it maybe 6 to 8in tall and stick in a pot. I have heard crab apples air layer pretty easy.

I had a mulberry air layer that looked like that. Put it in the ground and it took off like crazy.

Sorry, my pics clipped off the top and bottom, but that was after removing it. I stuck it in a pot just in case it might root/bounce back but I think it's done for.

 

[coh]

I've had that happen with crabapple air layers. There is one particular variety that is growing wild on my property. It has beautiful large white flowers, so I've layered it a couple of times. Each time, the layer produces a ton of callus the first season, but no roots. The second season it would usually produce a few roots (though one time I think it took until the 3rd season). I've managed to get 2 successful layers growing on their own roots. Other crabapple varieties have rooted heavily within a couple of months. I can't explain why the behaviors are so different. I've never had branches die above the layer, though.

I would have recommended re-wrapping it with moss and leaving it on the tree. Let us know if it makes it.

 

[0soyoung]

Sometimes rooting competence disappears with the onset of flowering maturity.

Death above the girdle is not unusual. It is just the compartmentalization response to the lack of auxin that is just like the branch had been pruned - the xylem gets plugged-up/sealed-off. It usually happens as a consequence of the cambium dying at the bottom edge of the girdle. Water, minerals, cytokinins, and ethylene precursors flow upward in the xylem sap. The death of just a few individual branches above the girdle are hard to understand having any direct connection to a layering girdle. Death of the cambium further down than the first branch below the girdle is difficult to understand as well. Photosynthates and auxin flow down the tree from the foliage in the phloem (inner bark) and cambium. Other messengers like RNAs move in the phloem sap.

Is it possible that branches from this layered stem were affected by some pathogen?

 

[W3rk]

Sometimes rooting competence disappears with the onset of flowering maturity.

Death above the girdle is not unusual. It is just the compartmentalization response to the lack of auxin that is just like the branch had been pruned - the xylem gets plugged-up/sealed-off. It usually happens as a consequence of the cambium dying at the bottom edge of the girdle. Water, minerals, cytokinins, and ethylene precursors flow upward in the xylem sap. The death of just a few individual branches above the girdle are hard to understand having any direct connection to a layering girdle. Death of the cambium further down than the first branch below the girdle is difficult to understand as well. Photosynthates and auxin flow down the tree from the foliage in the phloem (inner bark) and cambium. Other messengers like RNAs move in the phloem sap.

Is it possible that branches from this layered stem were affected by some pathogen?

Thanks 0soyoung - this attempted airlayer is from a very mature tree. I believe the parent tree has been flowering/fruiting since I first moved into this house @ 8 years ago. Good to know that that could be a factor preventing rooting.