Three major east coast thermal groups can be identified: (1)Tropical subtropical group shoot growth initiated >250C (2)Warm temperate group shoot growth initiated 15 25C (3)Cool temperate group shoot growth responds -10oCThree major east coast thermal groups can be identified: (1) Tropical subtropical group shoot growth initiated >250C (2) Warm temperate group shoot growth initiated 150 250C (3) Cool temperate group shoot growth responds ~ 100C