|I have a trellis in full sun near the entrance to my back garden for which I need a vine. I am thinking about Lonicera japonica|
|Decisions, decisions! You've chosen two outstanding plants -honeysuckle and grapevines - for your yard. Of the two, I'm leaning toward the honeysuckle. Lonicera covers a trellis with ease, it has wonderful fragrance when in bloom and it will attract wildlife. If grown in a sunny spot with adequate air circulation it should not develop powdery mildew. If it does, pruning it back to thin it out and encourage healthy new growth is the best approach to eliminating powdery mildew. As for grapevines, they are rampant growers and while they do produce edible fruit, the flowers are not terribly attractive. A single grapevine can cover a huge area in a short amount of time. Depending upon how sturdy your trellis is, you may end up spending most of the summer whacking the vines back so they won't be heavy enough to pull the trellis over. I planted a single grapevine and had it climb up to a deck which was 6' above ground level, then trained it up the 4' wooden deck enclosure, where it continued to climb up another 4' onto an open framework 8' above the deck. Within 5 years the vine grew enough to cover the roof and sides of a 20' by 20' deck. We had to prune it back to 3' above ground level every spring or the vines would become so rampant that they grew up onto a second-story roof. To complicate matters, local raccoons were tempted by the ripening fruit and they seemed to have a party on the roof every summer evening! I guess the bottom line is, unless you have lots and lots of room, I wouldn't recommend growing grapevines!
Best wishes with your honeysuckle!