Sally,
I am in your same zone and have not found the gojiberries to get out of control . Yes, I have dug 3 plants that came up from runners but they were welcome and I just replanted them nearer the mother plant.
I seems like if you did not want root runners a little pruning mid summer would keep this from happening.
To do this you just take a sharp spade and slice straight down into the ground about 12'' from the base of the mother plant.
As for taste I think I may have previously responded that they are not unplesent but also not too desireable in mu opinion. I grow them for their healthful qualities.
