Thuja burning up? Or something else?

[TeT12a_sPiN]

Grew this puppy from it's momma in my front yard. Looked down beneath the bush one day and saw this lil guy growing from the roots. So I cut it out and potted it up. Free bonsai woohoo.

It's about 8 or 9 yrs old at this point, and just this summer, parts of its upper foliage started turning brownish-orange.
I live in NJ; zone 7A. It seems to have been progressing little by little all summer. Does it look like heat stress? Or can it possibly be an over-watering issue? As a lot of trees on my bench are in inorganic bonsai soil, this thuja is in regular fast draining "cactus soil" with organics. For its whole life it's been in the same soil so I know that's not the issue. My point is, I water all my fast drying trees everyday, sometimes twice a day and this thuja just gets it also. So the soil may not dry out too much at all. Idk...it's weird it's only on parts of a few branches...can anyone pin point this issue? Heat issues or burning, maybe over-watering??

Any info would be much appreciated! Thanks guys and gals.

 

[cody94withrow]

Well you know someone's going to ask if you're really checking the soil first.
It looks loamy like it may hold water better than fast drain soil. Maybe it's got something to do with overwatering.

I know I had my juniper turn yellow on a spot because I had the original soil on the root ball, and I was only checking the fast draining soil around it causing me to overwater. Once repotted in the appropriate dirt it did much better.

 

[gooeytek]

How long ago did you dig it up? good root structure?

 

[MaciekA]

FWIW, a thuja is absolutely 100% bulletproof in pumice or akadama (or a blend of both which is what I use) if you're going to treat it as a bonsai.

 

[MACH5]

Thuja are moisture loving conifers. They often grow in areas with a high moisture content like near acidic bogs although also found in dryer areas. Your tree has good color. It looks like it is only the old foliage that is shedding which always occurs as autumn comes around. That may be the case. Tough to say just from photos but it does not look to me that your tree is unhealthy. Your growth tips look nice and vigorous which is often a reflection of root health.

 

[Orion_metalhead]

Agree. Looks like its just shedding old growth or growth not getting enough sun.

That doesnt look like a cactus soil mix to me. That said, like Sergio mentioned, Thuja do well with more water than less.

 

[TeT12a_sPiN]

Thanks for the comments everyone. Sorry for not responding quicker. I was picking off some weeds and moss on the surface and just left the top inch loosely leveled out so that's mainly why the soil looks that way.

I dug it up around 2016 maybe 2017. It was the size of a softball when I planted it up. Crazy, too, bc I barely cared for the thing until I recently got more into bonsai and paying daily attention to my trees.

The foliage towards the top of the tree continued to lose a single branch into September. Just sat down a few days ago and trimmed it all out. The tree is def healthy, maybe the sun not getting to the back side was the cause. Hard to say. It was just the burnt orange color of the scale-like-branch, along with the more mature, woody part of the branch also looking burnt which was causing my concern.

Figured I'd update this thread for anyone interested. I appreciate all the help everyone. Thanks.