Key limes are one of the most fantastic of all citrus; their unique acidic flavor is unparalleled. t the year, but the peak season is in the summer. They like hot, humid, full sun locations. Key Limes are usually no bigger around than a 1 inch and about as long. They are green and over-ripen yellow. The tree is bushy in habit and will grow no bigger than 12-15 feet. Key Limes are one of the few citrus that do not need to be grafted, but most are. Our dwarf trees are grafted onto Flying Dragon dwarfing rootstock (Poncirus trifoliata) syn. (Citrus trifoliate).