Only the Tree Dahlia rises above five to six feet tall ... The various colors of ‘Dark Angel’ Dahlia varieties, named after their black, chocolate-colored dark centers, are also a good choice for a 12 ...
Noting you should opt for early maturing tomato varieties that can withstand cooler temperatures such as Sungold, Gardener's Delight, Black Opal ... over by bare root roses, dahlia tubers, zinnia ...