Dahlia is a genus of bushy, tuberous, herbaceous perennial plants in the daisy family, Asteraceae, which includes sunflowers, daisies, chrysanthemums and zinnias. They are native to the higher elevations of Mexico and Central America. Many cultivars have been bred for their prized, ornamental flowers.

Dahlia campanulata, commonly known as weeping tree dahlia, grows naturally at high elevations in Mexico where there is a mild climate all year and nights are cool. During autumn this rare species has large, spectacular, white and purple flowers about 18cm across which are believed to be the largest flowers of all natural Dahlias. This is a deciduous species with large, 45cm long tubers sprouting new shoots each spring. The plant grows best with some morning sun and part shade during the daytime. It enjoys moist, well-drained soil and branches may require staking under windy conditions. Bring the tubers indoors in areas that have regular frosts in winter.