Ml_work

I have a Dwarft Cryptomeria / Cryptomeria Japonica "Tansu" that is dieing at the tip of one branch. Each time I cut or pinch off the dead growth it is back by the next day. The tree is very thick, but if you look on the inside their is new green growth. I have a feeling this could be root rot!
The tree has a nice cover of moss over the entire pot..( I know I should have already learned my lesson about that cool looking moss) the moss had been there most of the time I have owned the tree. This summer the tree is on my deck, it gets direct sun most all day. Late afternoon is shaded somewhat. When I water it runs off the moss, in the winter I just water slowly and it gets enough water. With the heat this summer I have started submerge the pot in my water barrel. It bubbles like crazy so I know it is dry. Also I think it is root bound, the soil is dry and hard. I looked today and the bottom of the trunk is wet and a bit soft. What I am thinking is it needs the water each day but the moss is holding moisture in no allowing it to dry at the top. I think it would be good to re-pot and prune some roots. I am afraid that my be too much stress on the tree at this point but do not want to loose it. My plan is to remove the moss layer tomorrow to allow air and be able to water with the water can and not submerge it.
You cannot tell much by the picture, I had uploaded a picture of the tree once before at someones request. The tree looks good except for the one place that you see in the picture.
Should I re-pot now, which would include root prune...woud this be too much?
Thanks for any ideas, I really don't want to lose this tree.
ML

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Dav4

I have a C. 'Tansu' planted out as a landscape tree...I've had maybe 3 years now. It browns just like that all over the tree, which is approx. 2' high by 3' wide. I've never been able to figure out why. We live in quite different climates, your tree is potted and mine isn't.... yet we have the same problem. The problem may be with the cultivar itself, I suppose. I'm not sure what to say to help you. If you think the tree is rootbound, slip potting into a larger container might help...you can get a good look at the roots as well. I think some mid day shade might not be such a bad idea either. Good luck,

Dave

Ml_work

thanks for the input Dave.
It's good to know this may just be the tree itself. I did not get the moss off today as I ran out of Day. Hope to do it tomorrow, it will allow me to water as normal. If it continues to look bad I may do the re-pot. Hope to get some more opinions in the next couple of days.
Thanks,
ML

T.S.Wheeler

If it is root rot I think you should be able to smell it around the roots. I hardly know how to diagnose the problem other than to agree with what has already been suggested. I have had several, and they all did the same thing for no apparent reason. I really like these trees, but I think they must be rather finicky. All of mine ultimately died, but only because I had to leave them in my parents care when I went to college and they didn't water them enough. Hopefully the problem with your tree is not serious, and I also would like to hear what anyone else has to say. Oh, and I think they probably would like a little afternoon shade from the intense Southern sun. I had mine in a pot with a larger lace-bark elm that provided dappled shade, and it seemed to like that.

Travis

Glider

I don't think you can smell root rot per se. There is a difference between root rot (the disease, caused by a Phytophthora infection) and rotten or rotting roots (the anaerobic bacterial process that happens to dead organic matter and produces hydrogen sulphide; the 'rotten eggs' smell of drains).

Phytophthora is a group of soil borne water molds that infects plants (phytophthora cinnamomi is the worst). Most are quite specific, but cinnamomi infects a wide range of plants and is extremely agressive. Plants infected with phytophthora will not usually survive. This is what causes the lethal 'root rot' that farmers, gardeners and bonsai people fear.

However, rotting roots is a different thing altogether. In soils that are very compact and often waterlogged, areas of root can die through lack of oxygen, or can have dried out and then been resoaked. These will begin to break down and decompose through the action of anaerobic bacteria and it's these that produce the rotten smell (hydrogen sulphide). They also turn the area black (absolute soot black, like swamp mud).

The good thing is that phytophthora is aerobic and can't survive in anaerobic conditions. If you repot a plant and find an area of soil that is soot black and smelly, that indicates that organic matter is decomposing anaerobically. This can be treated simply by removing the dead material and the black smelly stuff, washing the roots in fresh water and repotting in a fresh, open and airy mix. The anaerobic bacteria will die and the roots will heal.

If the roots are not soot black and don't smell bad, but are orangy in colour and soggy, where the outer sheath slips off the inner lignified root strand easily, then it's root rot (the infection) and the tree is lost.

I got two azaleas this year from a bonsai nursery. They were significantly underpotted and had probably been so for some time. The 4" root balls were very compacted and in both, one side of the rootball had begun to rot (probably the pots had been on a tilt and that side never drained). The areas were black and smelly. It took a couple of hours each to pick out all the old kanuma and black mush, frequently rinsing the root ball in a bucket of water. After being bare rooted and removing all rotten material, they were repotted in fresh, large grain (>4mm) kanuma. They are both recovering nicely and are starting to put out new shoots. That wouldn't happen with root rot, but they only had rotten roots.

Ml_work

Thanks for the info:
Travis, you said both of yours did the same thing....the red/orange dead limbs or the root rot...?
The tree gets afternoon shade after about 2pm. The house roof cast a shadow over it, I feel it gets a bit of relief.

Glider...it is Good to hear from you, it has been awhile. And as always I value your experience and opinion very much. And it doesn't sound too good as you describe my situation to the "T". There is no smell that you and Travis mentioned, so that is good...I guess. and no black soot roots...but: quote

are orangy in colour and soggy, where the outer sheath slips off the inner lignified root strand easily, then it's root rot (the infection) and the tree is lost.

Ouch!
That is what I am seeing at the base of the trunk were it comes out of the soil.
Now this is in the cedar family, so the bark does peel and it is orange to the color. This tree is so thick/dense that it is hard for light to get to the middle. If this is root rot, is it a result of too much water? The pot drains great..so it would be the moss?
As of today I removed almost all of the moss, leaving only about 1/2 to 1 inch around the outer edge. This way I can water as normal and it will have a better air flow. As I looked deep into the tree I see much new growth coming out. I am going to watch a few days to see if it drys out any. If not I will try to re-pot, but from what you say it may not be any hope for it.
Thank you both,
Have A Great Day!
ML

Glider

The sun is strongest between about 10am and 2pm. That's when trees need shade (if they need it at all). After 2pm, the sun is lower in the sky and so less strong. My azaleas can take direct sun before 10 and after 2 without suffering, but they would scorch if they got midday sun. If your tree needs protection from direct sun, then the best time for that protection is between 10am and 2pm.

Nice to be here. It's been a quiet summer so far.

IF you had a severe root problem (I stress the 'if'), then it would be better to have one that was smelly and black than one that wasn't. That was the point of my previous post: Root rot (phytophthora infection) is not treatable and is lethal, whilst rotting root (smelly and black) is treatable and is not necessarily lethal.
Soggy, mushy roots with no smell suggest phytophthora infection, which is lethal. However, from what you say, you haven't actually looked at the roots, and it doesn't sound like root rot. If it was root rot and had advanced to the point it was visible at the base of the trunk, your tree would have turned completely brown a long time ago.

Your tree has only gone brown in one area, so what I thonk you're seeing at the base of the trunk is simply the result of damp moss growing against it. Removing the moss is a good move.

If allowed to grow too dense and compact, moss will impede watering and airflow, but it won't cause root rot (although it might contribute to roots dying).

Good move.

If you see new growth, then the problem is not root rot. In fact, there is unlikely to be any significant root problem. This first thing that happens if there is a major problem with the roots is that top growth stops.

From the picture, the foliage looks quite compact. If you see new growth in there, then the roots are working. I would keep an eye on the bottom end (roots and soil), make sure it's draining well and keep it damp, not wet, but I would also thin out the top to let light and air into the foliage. Remove all the brown foliage and open things up a bit. This will encourage the new growth.

Also, give it some protection from direct sun between 10am and 2pm. Not deep shade, but light, dappled shade. If your tree is susceptible to scorching, then it's midday sun that will do it. Sun after 2pm is less strong (as I say, even my azaleas can take it then).

T.S.Wheeler

Glider, thanks for pointing out the difference between phytophthora and rotting roots; I had no idea, I assumed they were one and the same.

ML, all of my little cedars had the red/orange dead limbs; I think they would do this when they became stressed by anything, perhaps because of local environmental changes. I don't think it is necessarilly a sign of imminent death; I tried pampering some and gave them more consistent circumstances, and they responded well, but on other occasions I've had them die because the problem became rather advanced and I didn't really know what to do. I can't remember how many of these cedars I've had, maybe five or so, but I've never had a perfectly healthy one. All of them ultimately died, but I think that was because I (or my parents) let them dry out.

I didn't know you got shade as early as 2:00 pm, that sounds good to me. I know they wouldn't like too much shade, but that sounds perfect. Also, do you think you could pull some soil away from the surface to examine the deeper roots, or pull the tree out of its pot to see? I tend to doubt the problem is root rot as you mentioned the soil is free draining; although it is possible for the moss to cause the base of the trunk to rot. I guess... I don't even know if that is connected to the limb die back. That just seems to be a frustrating blight on the cultivar. Anyway, sorry I'm not much help; I would love to hear from someone with more experience what the real cluprit of the limb dieback is. I hope your trees get better!

Travis

noissee

i'm not too familiar with this species, but the advice to thin out the foliage seems to me to be the key. i've had a couple of junipers turn brown from too dense of foliage. i thinned them out and they recovered in a few weeks.

noissee

p.s. it looks like a species that would be pretty susceptible to spider mites. i would look into that as well.