Fungus or repotting stress

[Beng]

I repotted two Rocky Mountain Junipers last weekend and one of the two is showing random yellowing on about 1/3 of its needles. The more severe areas fall off at the slightest touch. The rest of the tree is a nice healthy green.

Anyone seen this before? It could be repotting stress as a portion of the roots were removed but I doubt that would cause yellowing like this in just one week. I was thinking it may be a fungus.
I'm contemplating spraying with copper or mancozeb but that will desicate the needles a bit so since its newly repotted I'm hesitant to spray.

 

[Brian Underwood]

One week? Typically it takes a while longer than that... Did it show ANY signs of yellowing before the re-pot?

 

[sean f]

That's happened on my shimpakus before
Went away but never sure what caused it
Always thought it was just old foliage dying

 

[dpowell]

I have a California Juniper that is doing the same after a very necessary, but rough repot. It's losing some clusters of needles after yellowing. One week does seem to be a bit quick as Brian mentioned, but I'm more inclined to blame it on repotting stress rather than a fungus. Regardless a fungicide spray is probably a good idea for all your trees this time of year.

 

[Beng]

Yep its been i think 8 or 9 days since the repot. It had a few yellower areas when I bought it but I figured it was just leaving its winter dormancy. The last 2 days have been unseasonably hot (mid 80's) so it could be a combination of the heat and a fungus.

 

[october]

Don't think it is a fungus. A fungus turns sections brown so fast, it almost skips the yellow phase. You will see every couple/few days, the foilage turning brown and dying. It could be scale or spide mites. I don't think stress would show up this fast. The good news is if it is stress, the tree is telling you it is sick by letting go of sections. If the entire trees turns a different color green shortly after a repot, then the tree is dead.

Rob

 

[bonsaibp]

Its a little early this year but our CA's and A RMJ I had go through this type of foliage shed annually- usually in May/June but this year its happening a little earlier, thats what it looks like to me. The first few years it scared the heck out of me until I found out what it was. About 95% sure not a fungus.

 

[garywood]

It's hard to tell from the pics but Junipers typically "yellow' interior foliage when root-work is beyond what that are capable of sustaining. Be it collecting or hard root pruning or stress in general. Allocating resources to growing roots is the first priority so interior foliage that doesn't' contribute as much as "tips" are sacrificed. If there are healthy growing terminals, not much concern.

 

[Beng]

Thanks guys that's good to hear. The root work was moderate in my opinion on this tree. There was one large 1 inch root which was about 6 inches and i pruned the bottom inch off it to fit it in the pot which only contained one group of feeders. The rest of the feeders 80% of them were up near the base of the tree. I left more then enough of the large root for possible die back. The past two days were warm so what Bob says make sense due to the warm weather. The seller also suggested I it's normal seasonal shedding for this type so I will let it be and see how it fares rather then spray it. One thing i'm sure it's not is spider mites as I have a good program going to decimate them in my yard and there's no way theres a spider mite alive anywhere.

 

[Dav4]

One thing i'm sure it's not is spider mites as I have a good program going to decimate them in my yard and there's no way theres a spider mite alive anywhere.

Where there's a will there's a way...I've found spider mites to be the most difficult pest to manage even with routine and appropriate spraying, so I would always be on the lookout for them. Having said all that, when one of my RMJ got mites last year, the foliage of the affected area turned from a nice, light blue to a sickly grey color. The yellow came months later when the foliage finally dried up after dying.

 

[Beng]

Try this rotation nothing can survive it from my exp.
http://bit.ly/1eaeoQg. Rotate one of those ever 3-4 days and then spray once a month with one of them after. Works great for me. I used to try thinks like neem oil but it just doesn't have the power needed to take care of them.

 

[Eric Group]

When you repotted, were any large roots cut? Sometimes you can cut the root of a major live vein, and it will cause die back farther up the tree...

Other than that, it is hard tot ell from the pics and info given- could be just about anything! Spider Mites seems to be the first thing people mention on Junis... Definitely want to check for them. If not Spider Mites it could be a fungus, but hard to treat accurately without knowing what kind.

I don't think it makes sense for this to be just a natural shedding for this time of year if you have another tree of the same type that is not shedding old needles right now...

 

[Vance Wood]

For what it's worth according to Kimura yellowing growth after repotting a Juniper is not always a bad sign it is a good sign that the tree is functioning and trying to balasce itself out after having roots cut. The long and the short of it is evidence that the tree is still alive.

 

[Beng]

When you repotted, were any large roots cut? Sometimes you can cut the root of a major live vein, and it will cause die back farther up the tree...

Other than that, it is hard tot ell from the pics and info given- could be just about anything! Spider Mites seems to be the first thing people mention on Junis... Definitely want to check for them. If not Spider Mites it could be a fungus, but hard to treat accurately without knowing what kind.

I don't think it makes sense for this to be just a natural shedding for this time of year if you have another tree of the same type that is not shedding old needles right now...

A large root was cut. It was about 6 inches long by 1 inch thick. The tip had one set of feeders coming off the side. The other 80% or more of the feeders lived up near the base of the tree which was 3-4 inches away from the area I cut. I only removed about an inch at the tip which had less then 20% of the roots. Time will tell.

 

[Vance Wood]

A large root was cut. It was about 6 inches long by 1 inch thick. The tip had one set of feeders coming off the side. The other 80% or more of the feeders lived up near the base of the tree which was 3-4 inches away from the area I cut. I only removed about an inch at the tip which had less then 20% of the roots. Time will tell.

This could be the source of your difficulty, the one large root you removed may have been the only life line feeding the portion of the tree where you are losing foliage, just a thought and as likely to be wrong as right.

 

[Beng]

This could be the source of your difficulty, the one large root you removed may have been the only life line feeding the portion of the tree where you are losing foliage, just a thought and as likely to be wrong as right.

Well if it was the whole root sure that would be bad for the tree but it was a small portion of it. Many feeders above it with plenty of area on the larger root for die back something like this.

 

[Vance Wood]

Well if it was the whole root sure that would be bad for the tree but it was a small portion of it. Many feeders above it with plenty of area on the larger root for die back something like this.

Not wishing to be the devil's advocate but you removed one large root with some feeder roots at the bottom. Those roots would not be there if they were not being supported by something topside and conversely the top side growth could have been supported only by the roots you removed. With Junipers we have learned that they can be very focused on life lines and will not necessarily share. Remove a life line, it is gone top to bottom. Just because you have an-abundance of roots someplace does not mean that the whole root system is connected equally to it.

 

[Beng]

Not wishing to be the devil's advocate but you removed one large root with some feeder roots at the bottom. Those roots would not be there if they were not being supported by something topside and conversely the top side growth could have been supported only by the roots you removed. With Junipers we have learned that they can be very focused on life lines and will not necessarily share. Remove a life line, it is gone top to bottom. Just because you have an-abundance of roots someplace does not mean that the whole root system is connected equally to it.

In my opinion this type of proportional root reduction isn't a problem for a healthy tree, I've done much more drastic things to junipers. The yellow growth was mostly yellowing in the middle of the tree which wouldn't make sense in regards to it being due to root reduction at the tip. They would most likely be supporting the top or bottom of the tree "probably the top." The roots of a tree usually mirrors the top. I've watched and assisted first hand in repots of much older trees where roots twice as large have been chopped off with less supporting feeders. The good news is tree seems to have stabilized and the yellowing hasn't increased. We jumped from 65 to 88 in 1 day and then stayed there for 3 days. I think it was most likely due to heat stress and it not being able to take up the amount of water needed to support the tree on it's new roots in the new environment (this tree came from oregon.) We're back down around 65 now and it looks like we're gonna be sticking there for the next few weeks. Great news since this will give the tree plenty of time to play catch up before summer.

As a test and precaution I sprayed a small portion of the yellowing needles with a mix of mancozeb and honor guard. That way if it does get worse on other parts but gets better in that area i'll know its fungal.

 

[Vance Wood]

In my opinion this type of proportional root reduction isn't a problem for a healthy tree, I've done much more drastic things to junipers. The yellow growth was mostly yellowing in the middle of the tree which wouldn't make sense in regards to it being due to root reduction at the tip. They would most likely be supporting the top or bottom of the tree "probably the top." The roots of a tree usually mirrors the top. I've watched and assisted first hand in repots of much older trees where roots twice as large have been chopped off with less supporting feeders. The good news is tree seems to have stabilized and the yellowing hasn't increased. We jumped from 65 to 88 in 1 day and then stayed there for 3 days. I think it was most likely due to heat stress and it not being able to take up the amount of water needed to support the tree on it's new roots in the new environment (this tree came from oregon.) We're back down around 65 now and it looks like we're gonna be sticking there for the next few weeks. Great news since this will give the tree plenty of time to play catch up before summer.

As a test and precaution I sprayed a small portion of the yellowing needles with a mix of mancozeb and honor guard. That way if it does get worse on other parts but gets better in that area i'll know its fungal.

Then it would be my first assessment I would go back to: A natural reaction from a functioning tree trying to balance itself out. Post #13

Just trying to help, sorry if I irritated you.

 

[Beng]

Then it would be my first assessment I would go back to: A natural reaction from a functioning tree trying to balance itself out. Post #13

Just trying to help, sorry if I irritated you.

Not irritated at all. I think you may be right. I've talked to a couple others in person and people seem to think it's either

A. Natural seasonal shedding.
B. The trees natural reaction to drop some foliage after repotting and seasonal shedding.

No one really seems to think it's fungus which is good. I'm not seeing any more decline so I think this tree may be just fine.