There is a new book 'The Gardener's Guide to Growing Hostas' by Diana Grenfell from Timber Press. It is very well written. We have had a grape vine in our yard for the past eight years and it has never had one grape on it. It doesn't even bloom. Sounds like the plant is getting too much good care.
Grapes thrive on a certain amount of neglect.
In fact, the finest grapes I have ever seen were planted around an abandoned house, where the only water they got was from rainfall. When we study the vineyards of France and Germany, we find the rows run up and down the hillsides for quick drainage. In the home garden the vines are too often planted in a spot where they get water whenever the lawn or flower beds are sprinkled. If the vines are growing long and fast, then there is a good chance they are getting too much care. A little vegetable garden fertilizer in mid-February will help, but then go light on both water and fertilizer for the rest of the growing season.