I also have a few plants grafted onto flying dragon, the oldest one being a pomello , I dont know if its the rootstock or my growing practices ,but the plant is tree years old and has grown very little, in past winters it has been wintered inside in a warm house, this year it is in a cold basement so I will se if this cold period acts as a stimulation for growing.... I generally like dwarfed plants ,but I really feel this should have grown more..