Alva's Supreme is a huge diner plate dahlia with soft creamy yellow flowers and very strong stems that can get up to 140 cm tall. Diner-plate dahlias are dramatic plants in any garden, but please don't try growing them in anything other than a sheltered site. They are most definitely a focal point, sure to turn heads, but bad weather can knock them over. Breed in New Zealand by V Frost in 1956