Buying container plants locally can be more expensive than ordering from a mail-order company. If you send away, your grapevines will probably arrive bare-root with a moist packing of peat moss or other material to keep the roots from drying out. The stem is usually cut back at planting. There is no advantage to buying a vine older than 1 year. Roots always have to be trimmed back at planting time, and no matter how old the vine is it takes a certain amount of time for the roots to reestablish themselves. Older vines won't necessarily give you earlier fruiting.