Wildlife will gravitate to food sources, so if you have a lot of problems with rats, they will likely try to take up residence nearby. That said, in my area we don't have that many issues with most rodents, so I really think it depends on your local conditions. Also, from my experience with grapes (which is limited) they don't usually grow that long/tall.

However, a couple things to keep in mind. Fruit plants attract bugs/bees/ants when flowering and during fruit production, and the fruit will litter your deck with discarded and spoiled fruit if you let them. I would make sure you think through the placement so you are not envisioning utopia, but rather realistic messes and discomfort.

Thanks for your response. I will need to think more carefully about this. Hubby wants to place a shade device instead. Such as a cloth or awning.

We have a vineyard, and also various fruit trees. The rats only like my favorite fig tree. Possums, Birds and Raccoons love the grapes. Grape pruning isn't that hard. You just let the vines cover your pergola. They will want to go everywhere, so keep the trunks rubbed off of new buds, and let the canopy grow. In winter they will go dormant. That is the time to prune (although you can summer prune also if they are getting out of hand). Each cane has many buds, depending on the length of the cane. Each bud contains a cluster of grapes and a new cane. Your job is to cut each cane back to 4 or 5 buds for next years growth and fruit. By doing this each year, you lessen the maze of old wood and increase the lush canopy of your dreams. Eat the grapes or make the wine and repeat every year.

Thank you Suzi. I do love the small old fashioned home grown grapes, especially when chilled. Any vine over a pergola is going to require some kind of care and pruning.