Ailing Rocky Mountain Juniper

Brian Van Fleet

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Mine do the same; old, interior foliage yellowing. Unlike Shimpaku, RMJ seem to hold onto it tighter. No rust, right?
 

Bonsai Nut

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The new growth that it is pushing is fresh juvenile/needle foliage - much stronger. I see this with junipers that have survived a period of stress and when they bounce back they throw a lot of immature foliage at the tips of mature/scale foliage. Just means the tree is on the right track. If I had to guess, the tree was either not fully recovered from being collected, or had recently been repotted and wasn't happy about it (?) I wouldn't do anything dramatic for a while - the tree needs some recovery time.

As Brian said, junipers will drop their old interior foliage. You just need to make sure it isn't due to fungus - particularly if you live in a humid area or have had tons of rain. We don't get rust here in Southern California, but we do get juniper tip blight (phomopsis). This last year we had a lot of rain and this spring was very hard on a number of my bonsai friends who got hammered by phomopsis. I have gotten very good at seeing what it looks like - and you don't have it - but if your juniper branches ever start to die from the tips inward - in spots here and there but not the whole tree - look up phomopsis and get ready to start an anti-fungal regimen.
 
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Vin

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Repot with half bare root in April. Roots were very healthy. I'm just going to put it back in the shade for a bit longer and give it time to bounce back. Thanks!
 

Dav4

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I'd put it out in full sun and not be worried about it at all myself.,,
This. I'd also look into grafting shimpaku onto it. I've got one with foliage just like that and it has never tightened up like I want it to. Last year, after 7 years of fighting the rank and lanky foliage, I started the grafting process. It's a long road ahead for me and the tree, but we'll both be happier in the end.
 

chicago1980

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I'd put it out in full sun and not be worried about it at all myself.,,
I have several RMJ and they behave the same way after a good repot and strong growth season. The shoots elongate first and then build up density. RMJ seem to drop the interior mature growth to support the new growth that is further out.

great movement in that tree!
 

Vin

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I have several RMJ and they behave the same way after a good repot and strong growth season. The shoots elongate first and then build up density. RMJ seem to drop the interior mature growth to support the new growth that is further out.

great movement in that tree!
Thanks! Great movement yes, but it's like some branch you'd cut off and throw away compared to that beast of yours. :)
 

chicago1980

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MACH5

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Mine do the same as well. Some more than others but will drop off old foliage. It always worries me if it wasn't for the healthy, growing tips. If a lot of rain is expected, I try and placed them under cover specially in colder weather such as in spring. Good luck with yours but I think it's fine! :)
 
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