The short answer is 8-10 feet for adult vines. VV is a Viticella hybrid, with some desirable and less desirable characteristics. From a practical point VV blooms profusely in the late spring (first half of May for me), but does better if cut back about half, which produces more branches, fuller foliage and flushes of blooms later. This keeps it from getting over tall, ending up with a mass of blooms at the top. Of course intermediate pruning can be done & if planted at a pergola or archway, a mass of blooms at the top may be desirable-your choice.

Wonderful... Thank you for all of your help!

Mine reaches nine feet and then flops back down at least half way.