I will be finding out this year.

I couldn't find any info on pruning Agarita (Berberis trifoliata), because generally it is not required. However, for some barberry species it is recommended to prune out the oldest stems of mature plants to ground level to spur new growth. With other species moderate pruning can be done to reduce size. Pruning of evergreen barberry species is usually done in spring after flowering.

In nature it seeds out in shade also and will get leggy. I have some that need to be tamed.

If I were cutting one back, I'd use the greenery for Christmas decorations.

I think it's beautiful.

ouch