Interior leaves turning color isn't cause for alarm, but the outer leaves rolling is as you suspect...

Leaves rolling in response to freezing temperature, flattening out again as the day warms, is normal - rolling and staying that way...not so good. It sounds as though you do not have adequate roots functioning to support the top growth.

As Morz8 alluded to, dry conditions or roots that can't pick up adequate moisture will cause the leaf curling. When you have this problem you must be careful to water, but not keep too wet. You may have had vole damage or weevil damage that made the stem loose from the roots. This would also account for the curled leaves. If it is from being too dry, then the leaves should uncurl when you water. If they don't, it may be too late.

If you have had freezing conditions, then it would be that.

Thanks folks. I'm pretty sure it's a problem with the roots. As loose as the stem is, it can't be getting much moisture/nutrients. I either picked a bad one or it was damaged in an early spring windstorm, because it's been an issue almost since the get-go. It's just frustrating after carefully tending to it for the entire summer and having it flourish for said time.