The Dahlia originated from Central and South America between Mexico and Columbia. the Dahlia is named after Andreas Dahl, who lived from 1751 to 1789. The original Dahlias were Dahlia coccinea, Dahlia rosea and Dahlia pinnata. From these single types, Dahlia Breeders have developed the Dahlias we appreciate today
The ideal location for dahlias is one in full sun. They will tolerate shade but should have a minimum of 8 hours of sun per day.
Height & Spacing
Dahlia plants vary in height from one foot to seven feet. Check each variety for its height and plant where suitable - the taller ones to the rear of the garden. Space you dahlias according to bloom size - the larger booming one should be planted two to three feet from other plants.
A stake should be used for any dahlia that exceeds three feet. Place the stake in the hole first then the tuber..
When to Plant
The time to plant in the Northwest is between April 15th and June 1st. The soil should only be slightly moist.
Water every two weeks -- more frequently during very hot weather, and when buds begin to form. A thorough. deep watering is better than frequent light watering.
How to Plant
Remove about 5 inches of soil, place the tuber flat with the eye upward, near the stake. Cover the tuber with soil; it should be about five inches below the ground. The tubers should be planted shallower in heavy soil.