Pictures (you may have to click on them to see the whole view):

definitely NOT crown gall, just normal wood formation.

Agreed. It simply appears to be normal "barking", the formation of the plant bark as the wood ages.

Than you, Paul & roseseek!!! Much appreciated (I tend to overthink these things).

You won't need an additional confirmation after our two heavy hitters have spoken, but that's a very healthy and good-looking rose. Carding Mill was a very good rose for me and stands up extremely well to the heat, although it also seems to be good in lower zones.

Kim, your added comments are very helpful. It's good to know that a plant doesn't have to be tossed right away and that something can possibly be done to save it.

You know, to ME, actual gall looks a lot like cauliflower.

and about as appetizing....

I love cauliflower.

SOMEONE has to.... LOL!

roseseek - thank you for your kind words - I really have learned so much about roses on this forum!

Jeri - I will keep an eye out for anything "cauliflower-esque"!

Ingrid - my poor Carding Mill is in a less than ideal location, in that it gets morning shade & afternoon sun. I have it there because visually it's a great spot for a rose, and I'm hoping that the heat tolerance will allow it to survive the sudden shift to afternoon sun. While it lives, it unfortunately hasn't flourished - if it doesn't improve after some TLC, I'll try moving it to another location.