Azalea regeneration

Paulpash

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One of my oldest friends from the bonsai club I used to go to has passed away :( the chairman phoned me to say she had left me this Azalea as a gift as I loved it's bright pink flowers. I think it's a kurume Azalea rather than a satsuki but I am not sure... If anyone can differentiate between the two I'd be grateful. I have had this tree a year now and it has not put forward much in the way of growth last season despite me feeding it.

Sadly it has been neglected (she was very ill) and the branches are quite leggy. There is also some die back in the trunk (the bark forms a darker spiral about 5 inches up the trunk). I think the roots under this die back have also suffered. I'd really like to be able to restore this tree to its former beauty but it does not seem very vigorous at all.

My request is an action plan for this tree probably spanning many years... A la brian van fleet!! First to get it healthy and then restyle. I've taken a few pics so you can see the problems I am faced with. I am new to azaleas so any tips regarding maintenance is appreciated.
 

Paulpash

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Ok these set of pics show the hollow in the trunk - if you look closely you can see the difference in the dead parts of the trunk. The darker area is dead (I think) and it spirals up the tree about 5 inches20120414_160741.jpg As you can see I have put the tree in sphagnum moss
 

Paulpash

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Some shots of the trunk and branch structure. If you look closely on the first spiral you can see the change on bark colour. Also there is a lifeline bulge on the trunk which gives me another clue the darker part of the trunk is dead.
 

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Paulpash

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Some shots of the roots - the area underneath the trunk die back is devoid of roots. There are bit of moss I couldn't get off without disturbing the roots further so don't confuse this with fibrous.

20120414_161825.jpg20120414_161857.jpg
 

Harunobu

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It is probably a kurume and probably on the R.kaempferi side looking at the leaves.

You can't really tell if a kurume is vigerious or not at this time of the year. It will be in dormancy and it will have dropped all it's spring leaves.

The rotting at the base of the trunk and the low amount of roots look very problematic.
I don't know how bonsai people deal with rotting trunks. But the rotting needs to stop, it needs to go out of dormancy and then it needs to grow a whole bunch of new roots.

I can't see any flower buds. But if it does have them, they will probably swell and show the first signs of petals within 2 weeks. Flower petals are modified leaves and it will lose moisture through the petals. The roots need to supply that water. Therefore it is safer to remove the flowers.

This azalea can be left out to grow uninhibited for quite some time. Especially the lower branches are not very thick yet at all. Little worry of reverse taper, which is somewhat common for very old azalea.
 

Paulpash

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I have gone through the tree and removed all the flower buds to reduce stress. Last year I painted the rotten area with wood hardener. Would a year in sphagnum moss be a good starting point for root regeneration coupled with appropriate feeding?
 

daygan

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My thought is that a good free draining non-organic soil along with proper watering and feeding would be all you'd need to help regenerate needed roots, (and maybe use a porous container for a pot like a pond basket or rice strainer for even more added benefit) but I honestly don't have enough experience to say that I have authoritative knowledge :) Maybe someone with more experience can tell you whether sphagnum moss will be better.
 

Harunobu

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Planting in purely non-organic substrate is possible with azalea, but they require constant watering. And that may be risky in climates that aren't humid. The roots need to stay humid.

Still the mix needs to be airy and well-draining. Coarse organic material with low pH like coarse fibrous peat, sphagnum fibers, and pine bark are good to use. Then any non-lime substrate is good. Because azalea grow such fine roots, porous gravel is really good to use.

Nurseries grow azaleas in 100% peat traditionally. But lately they are adding more gravel and pine bark. Mulch can also be very helpful.

In nature azalea grow on rocky cliffs where they root in the layer or humus and where they do get a lot of rain but never wet feet. That's what they want. They grow very bad in clay or mud and other types of heavy soil. In fact, that will kill them eventually. And they can't dry out like many trees can.

You already put it in 100% sphagnum? I don't think that is bad but it is not the most ideal mix you can create.
You generally shouldn't fertilize weak or sickly plants. If it starts to grow just fine maybe you can apply a bit of organic fertilizer.
It is easy to burn azalea with chemical fertilizer. If you decide to use it, use a much lower dilution than recommended.F
Fertilizer regime depends on the mix you use. If you used a substrate it is much harder to over-fertilize because you can just wash away excess minerals. If it is in sphagnum then it is very easy to tell when you need to water but you can't water aggressively because the sphagnum will hold a lot of water.
Too little fertilizer won't kill an azalea. Giving it too much will.
 
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Paulpash

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What to do about the die back and do you have any tips on improving branch structure (hopefully when it recovers).
 

Brian Van Fleet

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Marie,
Just seeing this for the first time. Harnuobu has given some good advice. The critical focus now is to stop the decay and get it growing strongly. Good move to have a look at the roots and address the rotting, also to remove the flower buds. Questions:

1. Did you find and remove all rotten wood and roots below the soil line?
2. What soil is the tree now in?
3. How much sunlight is it getting?
4. What did it do last year?
5. What and how often did you feed it last year?
6. How was it overwintered? Is it hardy in your climate?

You asked about die back, it's not important to do much with it now...remove it only if you can do so without disturbing the freshly potted root system. Until you see signs of growth, and hopefully some back budding from rejuvenating the roots, the best course is to ensure good light, proper watering, and adequate feeding.

You asked how to tell kurume from Satsuki, simplest way is that kurume bloom first, then grow foliage, satsuki grow foliage first then bloom...although both set flower buds in summer for the next year.

Let's see what the tree looks like now that it's been repotted. Although my climate is far different, I removed the flowers from my kurume over Easter weekend, and it's just now starting to leaf out.
 

Harunobu

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If you remove flower buds from kurume, they will leaf out right away rather than swell the flower buds. If you remove flowers from some shoots but not from others, you can see a clear difference.
Terminal buds that didn't get flower buds will grow leaves right away anyway.

You should be able to see signs of growth soon, if there are still none. Some kurume here are in flower. I haven't seen a kurume that has no signs of being out of dormancy when I did a round past the gardens in my area. But I am mainland Europe near the German border. So it warms up faster when it is sunny.

Don't really have any advice besides stopping the rotting and making it grow new strong roots.
I did see a video by Shibue satsuki garden, they started uploading videos onto youtube recently, that has an azalea that has a branch that died back and rotting at the base as well:
http://www.youtube.com/watch?v=fTLh2V7ZUS4
 

Paulpash

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Thanks for replying - I have watched the youtube videos and it's obvious my azalea is severely lacking vigour - i am sure if i hacked it back to the extent shown in the youtube vids it wouldn't make it.

I did some additional repair work on it yesterday (in the rain - but what's new in the UK??). As per Brian's recommendations I took it from it's pot and removed any dead root or indeed wood underneath (it sort of formed a black 'plate' of wood but was actually soft when pushed) so I cut this away with sharp branch pruners to what i considered 'live' lighter coloured wood (I did this slowly and nibbled away til I hit this). I then cleaned the pot it was going to sit in and took out the sphagnum moss it had been in temporarily for the last week or so. I sieved some fresh Kanuma soil to get rid of dust / small particles and added about 10-15% pine bark chippings. I secured the tree back in the pot, tieing it firmly with wire, and backfilled with substrate and used a chopstick to eliminate air pockets.

I then watered it for about 90 seconds using a hose til the water ran clear through the drainage holes and no Kanuma coloured dust could be seen. After this I placed a layer of sphagnum moss over the top of the Kanuma to try to keep the top layer of substrate moist, making sure it did not touch the trunk. The tree was then placed behind a bamboo screen and in the shade of other bigger bonsai on my benches that would give it good shade throughout the day. I then crossed my fingers and said a little prayer :)

Hope this was all sensible stuff to do!!
 

Paulpash

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Answers to questions:

1. Did you find and remove all rotten wood and roots below the soil line?
2. What soil is the tree now in?
3. How much sunlight is it getting?
4. What did it do last year?
5. What and how often did you feed it last year?
6. How was it overwintered? Is it hardy in your climate?

1. Yes - all rotten wood has been nibbled back to lighter, live wood
2. Sieved Kanuma soil and pine bark chippings (10-15%). The soil surface has a layer of sphagnum moss to maintain humidity & moisture in the top layers of soil.
3. Some very early morning sun then semi shade for the rest of the dat behind a bamboo screen
4. Last year it flowered very well but put on very little vegetative growth
5. I fed it every 2 weeks with full strength ericaceous fertiliser and chicken manure twice in the growing season
6. It was overwintered outside, wrapped in fleece, placed under the benches off the floor. I am in the UK - Kurumes are hardy in our climate up to around -8C. If it gets any lower i take it in an unheated garage temporarily.
 

gve

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Hi there Marie. I followed your thread with interest. Had some azalea myself, but had to restart after I moved back to SA from mainland Europe. Can you give an update on how it is doing now, please with some pictures if possible.

Thanks
 

edprocoat

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Marie1uk I was wondering too how this plant made out after the extra pruning and repotting so late in the season, then of course I REALLY HAVE NO IDEA IF THAT WOULD BE LATE SEASON IN THE UK. LOL :p I know it would seem late here in the states to do that type of work, especially after already changing the potting mix already and then doing it again. Anyway good luck with your Azalea I hope it works out for you.

ed
 

Paulpash

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Hiya,

Update on the azalea. I left it alone all season, but was tempted to peek at the root system to see if it was responding . I gingerly removed the tree today & the roots are now colonizing the kanuma and they are light coloured and healthy :D. I'd say another season and I can move it to a bigger container. I think it best to keep the root volume as high as possible and get it romping away ... some major cutting back will be needed to restyle the branches. However, initially, downsizing & placing it in a smaller pot was a good move least season

As you can see there is a little back-budding now in the crotches of several branches. I have also dug out some more of the dead wood as it was very pulpy. A few unsavoury critters were hiding in the crevices and in the dead wood so i am glad I did this.

A few pics ... You can see the dead spiral of darker wood on the trunk and the bulge of the live vein next to it. I've dug out the flaking material that nasty insects were making a duvet out of.
 

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Paulpash

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Some shots of the sparse branch structure and the tree as a whole. Any tips / articles / timing on branch regeneration of Kurume would be welcome.
 

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Paulpash

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Some shots of the branch pads. They are still lacking volume but the signs of increased root vigour is there with some back-budding occurring.
 

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