Advice on very old Azalea bush

[Unearthed]

Hi All,

I have this Azalea bush in my yard that I believe has a lot of potential to be a very unique, old bonsai with a few years of rehab. I live in 5b, but this bush is planted right next to the house in a brick built-in garden box... been here long before I bought the house. I think due to it slightly being outside its hardiness zone, but getting just enough warmth from the house... it's survived all this time, but has a LOT of deadwood throughout. Many of the branches only have a small live vein through it... and this year it's looking extra-sad (had a couple brutal winters past few years). To save it/potentially get a beautiful bonsai out of it... I want to try and dig it up/prune/repot, and maybe move it to a cold frame for the winter to establish some new roots before dormancy.

However... as I'm still fairly new to this world of bonsai... I wanted to get some help from some more experienced people (so I don't kill it! I'm really excited about this one!).

A few questions I had:
1. Do you think now's the time for any sort of movement? or should I try and overwinter it in-place and work with it next Spring?
2. If keeping it in-place, what sort of steps/prep should I do to ensure its survival through another brutal New Hampshire winter?
3. If repotting, should I got with 100% Kanuma? a mix? and I'm guessing I shouldn't do much root pruning until it's healthier & just use a larger pot?
4. How much should I prune it, when the time comes? I want to have decent amount of deadwood for jin/shari fun, but it's pretty bramble-y at the moment. Worried about not enough back-budding.
5. Best guess - how old might ya think this is based on size/trunk diameter?
6. Any other tips/suggestions to help get this tree into a pot & on its way to bonsai would be MUCH appreciated!

Thanks,
Jeff

 

[Glaucus]

It needs rejuvenation. I would dig it up next early spring, wash away some old soil, then put it in a new fresh and good soil mix.
Could be just garden soil and back in that old box. Or add some perlite or similar and put it in a large horticulture pot.
Do not use 100% kanuma. If you want to transition to kanuma, wash away as much soil as possible, and put it in 50/50 soil with kanuma first.
If you do a really excellent job at removing all the old soil, you could probably get away with 100% kanuma. But my feeling is that the roots also have to adapt a bit to the new medium.
Azalea in bonsai pots benefit highly from kanuma. However in larger and deeper horticulture type pots, 100% soil or a mixture of soil and substrate work fine.
I would bury all the roots under the soil level, for now. I see some signs of soil being washed away and roots being exposed. Better to keep them covered by soil, or mulch, while recovering.
But also prune out some of the dead and weak branches. This will direct the energy it has stored to fewer branches. So it should be able to grow more on those.
With very old azaleas, often the level of ramification has outgrown the potential for growth. And the new growth is spread out really thin.

Then indeed there is the question if the zone 5 winters make the azalea look a bit worse every winter, as you hypothesize.
Definitely being right next to the house will shelter and keep it warmer.
But this plant has been there for a long time. So it had many cold winters. So one kinda has to think it ought to be ok in zone 5 as a mature healthy landscape plant.
But it is not healthy right now. And you plan to do major work on it. So definitely it would benefit from either mild winters, or sheltered winters.
Check out the wintering guide: https://www.bonsainut.com/resources/overwintering-bonsai-–-theory-planning-and-case-studies-azalea-focus.49/

Not so sure about if you should dig it up right now. It should already be dormant or near dormant. If you had a heated greenhouse, I would say 'go for it'. But it then would be in a cold frame.
So that just means it has to go through winter with less roots and less stems. If you do it right as the roots are about to wake up, so late winter/early spring 2023, it already went though winter and it is about to grow those new roots.

 

[Deep Sea Diver]

One springtime idea would be to gently rake out the top 6” of soil all around the plant. (Use a small hand rake, pulling outwards from the trunk.) Then backfill with a mix of soil and amendments. Say 30% soil, 30% bark, 20% peat moss and 10% composted cow manure.

Then do some cutting back with the tree in place, ensuring each cut is sealed with something like New Kyocurl, Top Jin and for the branches 1/4” and more with putty once the seller dries. (See image you want the green top putty with growth enhancer.) Be sure to leave some green on each branch you want to keep.



Then wait, water and see how the tree responds. If it backbuds well with new growth let it grow for a year in place. This will give you time to study the tree, learn more about azaleas and get the equipment in place for digging the tree up. This will ensure both the tree and you are ready to do a good job of it.

cheers
DSD sends