Dahlia imp Double White 08-01-2019DianeComments are closed Tree Dahlias grow between 3-4 m and have large bunches of flowers mid to late autumn. They are herbaceous. Unlike many other Dahlias they do not need to be lifted in winter. to 4m. Tall bamboo like stems. Double white flowers in Autumn Category: Shrubs Related products Indegofera Decora Cotinus Grace- Smoke bush Loropetalum Bobz Pink Hebe Lavender Lace