January 17, 2015
Dahlias are a genus of bushy, tuberous perennial flowering plants that are native primarily to Mexico but also extending further down into Central America and Columbia. Spaniards discovered the flower in Mexico in 1525, where the indigenous population used the plant not only as a source for food, but also as medicine. With at least thirty-six known species, and thousands of different varieties, Dahlias, which is also its scientific name, are a member of the Asteraceae plant family, which includes related genera such as Cone Flowers, Daisies, Chrysanthemums, Marigolds, Sunflowers and Zinnias. Like other flowers in the Asteraceae family, Dahlias appear to be a single bloom, but in reality are made up of many individual flowers. Although this plant produces a gorgeous flower, its bloom does not generate a scent, thus it relies on its stunning colors to attract the insects required for pollination. Dahlias bloom from mid-summer up until your region’s first frost in the fall.
Dahlias should be planted around the middle of April through May, again depending on the region, when the threat of frost is no longer prevalent. The ground temperature should be at least sixty degrees. In much of the United States, these plants do not survive the winter, thus the tubers (fleshy roots similar to bulbs) need to be dug up every fall, and replanted each spring. Before the first frost of fall, these plants should be cut back to six inches. After digging up the tubers, shake off any soil, and then store in a frost-free place. Generally, forty to forty-five degrees is best suited for the tubers.
This plant requires eight to ten hours of direct or somewhat filtered sunlight each day, but especially love the morning sun. Less sun results in taller plants and less blooms. They thrive best in a cool, moist climate, while doing poorly in hot, humid weather. If your summer temperatures routinely exceed ninety degrees, these flowers should be planted in an area that receives some shade during the hottest part of the day. The flower thrives best in a rich, well-drained, slightly acidic, sandy soil. If your soil is too heavy or clayish, sand and/or peat moss can be added to lighten it. Dahlias are considered deer-resistant, though no plant is, in truth resistant to hungry deer. Dahlias are, however vulnerable to slug and snail damage.
With so many different varieties of Dahlias, the plant varies greatly not only in height, but also in the color, shape and size of the blooms. These flowers range in height from miniature six-inch plants to tree Dahlias that can grow more than fifteen feet tall. Larger plants will requiring staking. Colors range from white, yellow, orange, bronze, lavender and pink to red and purple, as well as dark red and dark purple. Blooms range in size from two inches up to twelve inches in diameter. Mature plants are as wide as they are tall. The large variety of blooms are due to the flowers being octoploid, meaning they have eight sets of homologous chromosomes, whereas most other plants have only two.
The tubers should be planted horizontally four to six inches deep, spaced roughly two feet apart. After covering with soil, the tubers should not be watered, as it can lead to rotting. Do not water until the tubers start to spout. In addition, tubers should not be mulched, as mulching does not allow the soil to warm enough for the tubers to spout. Mulch can be applied once the tubers do spout. Young plants do not require much water, again too much watering leads to rotting. Mature plants should be watered only if rainfall is less than one inch a week. If you are like me, and live in a region with freezing temperatures during the winter months, Dahlias can be grown in containers, however these plants only do well in large containers, generally they need pots at least twelve inches in diameter per tuber. Dwarf Dahlias are best suited when using containers. You should use two parts top soil along with one part of potting soil that has not been chemically treated for weeds.
If I am fortunate to have you view my photographs and you find the color saturation too much or the color schemes of the mats do not match either themselves or the photograph, please let me know via a comment. Being color-blind, what might look great to me might look like sh*t to everyone else!
Steven H. Spring