I have a couple of grapevines that were planted 3 years ago.
The first year, they didn't do much.
The second year, there was lots of growth, but only a couple of grapes.
This year, I pruned it back quite a bit (I have 3 vines in an 8' garden) but each of the vines has 3-6 shoots coming right out of the ground. Should I trim these off now, or wait until fall?
It's a good idea to prune them now before the normal pruning time. They are not going to be useful for the future of the vine or fruit in the short term so they are a waste of energy that would go to other parts of the vine.
My father-in-law (who has been growing grapes for decades) came over on the weekend and cut off all the shoots. When I asked him about it, he said that none of them would produce any grapes this year, and they'd end up getting pruned next spring, so there was no harm in pulling them off now.
You should wait till winter, and prune around mid to late Feb. Whatever growth you have now, you should let be.
Generally, this is a good resource: http://ohioline.osu.edu/hyg-fact/1000/1428.html
