Hi vics,
Lonnie and hillhogs advice is good I'm sure, but you may get the odd time when the sucker comes up from well below ground from the rootstock and short of digging to trace it back and causing a lot of root disturbance, heres a little tip an old gardener showed me many moons ago- Take a dutch hoe (or a small spade if the sucker is large), possition it between the sucker and the bush and plunge it sharply into the soil and hopefully the sucker will come away neatly from the bush.