Juniper woes...any help?

[coh]

Junipers are driving me crazy.

Last year I posted a thread about a shimpaku juniper, asking for styling ideas ( see http://bonsainut.com/forums/showthr...styled-quot-shimpaku-any-thoughts-suggestions). Got some good suggestions but since I couldn't decide which way to go, I decided to let it grow for another year.

It did OK last summer, came through the winter looking great, but recently has started going downhill. Significant parts of the foliage mass are yellowing/dieing off. I've attached 3 photos of the foliage below.

I've checked for mites and have not found any. Thinking it might be a root problem, I pulled it out of the pot and found an intact, healthy looking root system with significant amounts of new growth, at least along the sides and bottom (see last 2 photos). I don't know how the inside looks but the root mass held together pretty solidly.

Any thoughts would be appreciated. The tree is fertilized every 7-10 days with a rotation of liquid fertilizers. I have not used any fungicides this season but am not sure this looks like a fungal problem? Am willing to try if people think it might help.

Chris

 

[Dav4]

How's the drainage in the pot? The roots look good...only thing I can think of is the tree being root bound.

 

[GrimLore]

Perhaps to much fertilizer and not enough misting? I only fertilize Junipers in the Spring and once prior to the heat wave in Summer. Everything else looks ok to me...

Grimmy

 

[october]

Your tree is, most likely, prefectly fine. That is normal shedding. When the foliage turns a bright yellow and starts falling off quite quickly this time of year, it is shedding. Let the tree do it's thing. Just a heads up. Sometimes they shed so much it seems like it is cause for alarm. Just leave it alone. Also, in my opinion. I would cut back on the fertilizer in general. I would only fertilze every 2 weeks.

Rob

 

[coh]

Appreciate the input!

Seems like a bit too much to be normal shedding...I've had this tree for about 3 years now and have never seen this degree of yellowing. Whole branch sections are going to be gone. I guess in a way that will simplify styling decisions...

Drainage seems fine, root mass definitely doesn't seem to be too compact, at least not compared to some I've seen. I did slip it into a slightly larger container. Will consider cutting back the fertilizer.

Chris

Rob, you've mentioned fighting fungal problems on your junipers in recent years. Can you remind me what the symptoms were? How did they differ from what I'm seeing?

 

[Dav4]

I would agree with Rob except that, in at least one of the pictures, it appears that the yellowing foliage is toward the top of the tree, appears to be involving an entire branch and not older, interior foliage, and is unshaded by other foliage. To me, that isn't normal foliage shedding, but I don't have any other explanation for it.

 

[garywood]

Chris, you said it grew last summer. Did it get any extension shoots at all or were they cut off?

 

[edprocoat]

Coh, its hard to see in the pictures clearly but it looks like at least 2 of the affected branches are wired. I wonder if they were injured by the wiring and the tree is just letting them go. Usually when I slip pot a plant I rough up the edges of the roots to encourage them to grow into the new medium.

ed

 

[coh]

Chris, you said it grew last summer. Did it get any extension shoots at all or were they cut off?

Gary, I didn't do any pruning last summer. It didn't grow a lot last year, and there weren't any really long extension shoots - just slow, steady growth at the foliage tips.

No long extensions this year, either. Some of the foliage tips are healthy bright green and slowly expanding. Other areas are just yellowing and dieing off. Doesn't appear to be related to wiring.

Chris

 

[garywood]

Chris, it has the classic look and growth habit of chronic under watering. Everyone is familiar with acute under watering where the soil dries and wilting or dying happens fairly quickly Chronic under watering is where the core has dried from not watering sufficiently. Once this happens it's almost impossible to rehydrate with normal watering. I don't know what soil the tree is in but usually this condition happens with soil that contains organics in larger amounts.

 

[coh]

Chris, it has the classic look and growth habit of chronic under watering. Everyone is familiar with acute under watering where the soil dries and wilting or dying happens fairly quickly Chronic under watering is where the core has dried from not watering sufficiently. Once this happens it's almost impossible to rehydrate with normal watering. I don't know what soil the tree is in but usually this condition happens with soil that contains organics in larger amounts.

Yeah, it does have that kind of look.

The soil looked fine. I don't remember exactly what components I used (it was repotted in 2012) but it was a fairly "standard" bonsai mix. There was an organic component but not a huge amount. It is possible that there is a dry core buried in the center but I from what I could see, the soil looked OK. I think I'll have to plan to do a more significant repot next spring and see how things look deeper within the root mass.

It may be that I was underwatering it earlier in the season, though.

Thanks,

Chris

 

[october]

Appreciate the input!

Seems like a bit too much to be normal shedding...I've had this tree for about 3 years now and have never seen this degree of yellowing. Whole branch sections are going to be gone. I guess in a way that will simplify styling decisions...

Drainage seems fine, root mass definitely doesn't seem to be too compact, at least not compared to some I've seen. I did slip it into a slightly larger container. Will consider cutting back the fertilizer.

Chris

Rob, you've mentioned fighting fungal problems on your junipers in recent years. Can you remind me what the symptoms were? How did they differ from what I'm seeing?

Fungal disease problems on junipers are usually brown. The brown travels at a very fast pace. The stems and the foliage turn brown in sections. Your tree does not have a fungus. It could be a watering issue. However, I think it is just shedding. Shedding takes about a month or so. After this time, the tree usually puts on a large amount of growth. If in a few weeks time this problem stops and you notice a lot of new growth, you will know it was shedding.

Rob

 

[coh]

Hope you're right, Rob! But at this rate there's not going to be much left of the plant in another month. I'll post an update later in the season.

Chris

 

[jk_lewis]

As you are in Rochester, I'd suggest you take the tree to Bill Valavanis' place for diagnosis -- though I tend to agree with the underwatering suggestion. Maybe an X slice through the bottom half of the rootball and combing out the roots would help.

 

[Neli]

I think Garry wood is right. You might have a hard root mass in the center and water is not reaching there while the roots on the outside where the water passes are fine. Try to water the tree few times by submerging it in a bucket for 5 min, and make sure you water long and slow so water penetrates the center.

 

[Vance Wood]

Try moving the tree in to more shade. See what happens.

 

[Poink88]

Looks like old leaves shedding. The ones outside are from weak branches that didn't get new growth and only have old leaves. That is what it looks like to me at least.

Your tree should be fine but I agree to give it a little afternoon shade.

 

[goosetown]

Could indeed be shedding, though the shedding on these types of trees (and I have many of them) tends to happen to inner branches when occurring naturally (as many have mentioned). So that seems an unlikely culprit to me unless there is something blocking any sunlight to this particular outer branch.

Shimps also will tend to, at various times and for no explicable reason, throw a branch. You can be doing everything right and one will simply die off as the tree diverts nutrients to another section of itself. There may be a good explanation out there for this, but I haven't seen it yet. It's very frustrating, but hey, nature! That said, it almost always happens to lower branches, and your tree seems to be primarily affected in the upper portions, so again, that seems unlikely. Also, as a few have said, a die-off produces brown foliage, not yellow.

It *could* be an underwatering issue, and that has to be taken seriously since none of us know how you watered it before. However, you have to really screw up watering a shimp to underwater it, especially in soil that has some organic composition to it; overwatering is far more likely, but your roots are healthy and show no signs of rot. Therefore I wouldn't rule out underwatering, but I also wouldn't consider it likely. If you are SUPER worried about it, you could always comb out the roots a little and check, then slip-pot it, but that feels a little extreme to me.

Here's what I've learned from my shimps: they don't like to be bombarded with ANYTHING - sun, water, pruning, etc. They're good at taking a lot of little lumps, but getting too much of one thing at a time really tends to stress them out. Thus, I think your most likely culprit here is your fertilizing, which seems VERY aggressive to me for these particular trees. I think, at most, a cycle once a month with a slow-release fertilizer in the growing season is going to be your best friend. I've purchased most of my shimps from Gary at Chikugo-En nursery in Southern California, and he's always recommended a pellet-based slow-release fertilizer be applied at a rate of once per month max. Unfortunately I'm traveling at the moment and can't tell you the chemical make-up of the stuff that he sells, but I will do so when I get home this weekend if you think it'll help.

I keep my trees in a soil that, it appears, is much like yours - some organics, some inorganics, with some extra akadama mixed in and a layer of akadama constituting the base of the pot. Again, this was an approach recommended by Gary himself, and it seems to help the fertilizer break down and disperse naturally.

Here's the tough part, and unfortunately this is going to have to be left up to your gut (or, if you can get one, a professional's in-person opinion): you may want to just hold off completely on fertilizing until the tree bounces back a bit. Fertilizing a weakened tree may do more harm than good in general, and this is especially true of shimps. For now I, personally, would consider stopping fertilizing, watering it normally, and seeing how it responds over the rest of the Summer.