If it's an evergreen cultivar, you should only have to prune out tired looking foliage. If it dies back in winter, it should be cut back in spring.

It has about 80% still green and the rest are brown, so I guess I will have to go in and snip them out individually. I do like the looks of these plants. Thanks

Out of curiosity...how moist is the soil you're growing the Juncus in?

I got some seed from Juncus patens 'Carman's Gray' and I plan to start it this spring. I'm wondering if I'll have to give it bog-like or marginal conditions, or if it'll grow in just fairly moist conditions.

My plants are in heavy clay soil on the NE side of the house - so mostly shade. I moved them from my back acre, where they appeared. I love the form of the plant. They are definitely not in any very moist area. The back is full shade with large trees - yellow poplar, river birch, oak - and lots of invasive ivy, honeysuckle and privet. I guess the clay soil helps to hold any moisture they get.
Do you winter sow your seed?

I'm going to winter sow some, and spring sow some. I doubt if it needs cold stratification, but just in case, I'll try some that way.