I don't know of a vine that keeps it's leave throughout the season in Zone 6. I would recommend however, a clematis. A beautiful purple one, like Jackmanii, maybe combined with a white one, like Huldine. Both are vigorous growers that will cover your trellis in no time.

Gelsemium sempervirens "Margarita" ("Carolina jasmine") is hardy to zone 5, evergeen and covered with nice yellow blooms in spring. It grows well, but has thin shoots that are quite easy to trim and control.

You should know that it's considered poisonous, but then so are many common garden plants, so be aware of that.

You can find an image online. If you decide to grow it, be sure it is the "Margartia" variety, since it is one or two zones hardier than the standard types. I have grown my four plants here in Rhode Island (zone 6) for over 12 years and it has never had any damage. The leaves stay green all winter, which is one reason why I really like it.

Ditto bill, also major wheeler honeysuckle, red or it comes in yellow.

my red comes from se tex and is thriving here in z5. It is evergreen to.

hummers love it.

Thanks for the recommendations! I've purchased both and will see how they do