I'm re-posting this question from the wrong forum....

This Threadleaf Arborvitae has been perfectly healthy for 3-4 years now, and looked good through the summer. But now I'm noticing some browning, mostly in the interior of the plant. It's the dry, crunchy kind of browning.

Is it from a lack of water? The summer was somewhat dry, but the plant looked fine through it all. There's been plenty of rain in the last month or so, and now all of a sudden it's getting all brown. Maybe a lack of nutrients? I gave it some food in the spring, but I never gave it anything after that.

How concerned should I be?

Here is a link that might be useful: {{gwi:279852}}