The Dinnerplate Dahlia 'Omega', a spring planted tuberous root, produces orange flowers with a pink blush. Cactus Dahlias are the ones with the cactus-like blooms, often in super-bright bicolors, always with the rolled, pointed petals. Like other groups, Cactus Dahlias can be of various heights, as long as they have "cactus" flowers. The word dahlia means "plant with tube- like stems". With a blast of different colors, shapes and sizes, Dahlias bring life and beauty back to your landscape in late summer and into the fall months. The diversity of Dahlias allows you to use them in many different aspects of your landscape design, from low growing border plants to stately background plantings which may reach six feet in height. Dahlias make excellent cut flowers, which typically last about a week in the house.