Whether from oldest needles dying or shaded from the the outer shell of green, interior browning is normal especially at this time of year on all conifers.

tj

New Cedars.

Older Cedars, I can't say I've ever seen them brown like this.

Thanks tj, that's what I figured. Should I pull them off or will they fall off on their and return to golory green next Spring.

That seems excessive and not limited to the interior. Not sure if bagworms are in Monteal, but that looks like the damage they might do.

tj

While tj's statement is correct, the amount of browning I see (especially in the first photo) is not exactly "normal". They are showing signs of flagging or the drying and browning of second year or older growth, typically as a response to stress, like excessive heat, insufficient water, hot winds, construction damage or other root disturbance, poor planting procedures, or recent planting. It is most common and tends to be very visible in late summer and early fall. Generally, later fall and winter rains and storms will shed most of this dead material.

We see this routinely at this time of year with our native Western red cedars, Thuja plicata, but any Thuja can develop flagging. This year the flagging is extensive and very pronounced on our WRC's, as the summer here has been very warm and abnormally dry.

tj, do you believe that's the case for both photos I posted? It's definitely worse on the mature ones. How do I properly diagnose the issue and if it is a bug what can I do?

Not a bug and you don't need to do anything. At most it is a seasonal issue. Flagging never killed a cedar :-)

no evergreen plant holds its leaves forever ...

annual shedding of the older interior leaves is ENTIRELY NORMAL... and can be increased by any stress ... bad last winter.. drought.. and especially transplanting ...

if you look inside any mature conifer.. or evergreen.. they are all bare .. because as the vibrant exterior growth shades out the interior old leaves.. they yellow.. then brown.. then fall off ... again.. entirely normal ...

just water deeply and properly with near drying between deep waterings ... and focus on the growth tips... and as long as those stay green.. you are all set ...

also keep in mind.. though the pix are a bit vague.. they look like large transplants.. and you really have no idea if they were field dug for sale.. and that can be a lot of stress ...

i will bet my shiny penny .. now that youve noticed it on yours ... as you drive around town.. see if you dont notice it everywhere ... this would indicate the general drought or bad winter .... as compared to the transplant stresses ...

just water properly.. they are stressed.. they are not hungry.. fert is not a response to stress ....

ken

i was just thinking yesterday.. i ought to pull up the old post on interior yellowing ... its just that time of year ... and because of planting stresses ... it is a bit worse ...

Thanks Ken, I thought the same, "look at other Cedars in the area". It was hot dry summer here in Montreal too. I was consistent at watering my newly transplanted ones and they did well throughout the summer and look worse now with the cooler temps. As for the mature ones they didn't get as much attention from us so could be why they don't look great right now.