I have a few grapevines trained onto a pergola. I was thinking of planting a few perennials like roses and geraniums at the base of the pergola on all sides except the front. However my vines are planted a little more closer towards the center rather then towards the edges of the posts. Will my roses struggle to grow next to the vines or would they be ok? How far should they be planted from the vines?
Ten years ago it was fashionable to plant roses within few feet from grape vine (just on the border of a vineyards): roses help keep some insects which will protect the grape vines.
On olden time, it was used to have a tree near a grape vine: it is a vine, it needs supports (and iron was expensive and used for other stuffs).
So you should not have problems (in general). You will have two plant nearby, so there could be more competition (nutrients, water, sun). You should care that both will get enough of each component, and you will not have problems.