Dahlia flowers are blooming plants that yield blossoms in a wide variety of sizes, shapes, and colors. They originated in Mexico and are the country’s national flower. Dahlias have been cultivated in Central and South America since the pre-Hispanic era. Indigenous words for the flower referenced its hollow stem, but the current name derives from the Swedish word for valley. Dahlias were first found growing on sunny mountain ranges in well-drained volcanic soil. Today they are a flower garden staple in temperate climates throughout the northern hemisphere. The following will outline essential facts about dahlias and how to grow them.
General Info on Dahlia Flowers
Dahlias are herbaceous perennials–they don’t have woody stems above ground, and they live for more than two years. They’re also members of the Asteraceae family, a widespread group that includes daisies, sunflowers, and chrysanthemums, among many others.
Indigenous peoples in central Mexico and Guatemala valued the dahlia’s tuberous roots. They harvested these potato-like tubers for the insulin inside them and the antibiotic compounds in their skin. Francisco Hernandez, personal physician to King Phillip II of Spain, spent time among Aztec herbalists and reported that when consumed, the roots of the dahlia flower calmed swelling, alleviated stomach pain, opened blockages, and staved off coldness.
Like their Asteraceae cousins, dahlias are quite easy to grow from seeds. Their leafy stems can grow as short as 12 inches or as tall as 8 feet, and the flowers can have diameters up to 1 foot wide.
Main Varieties of Dahlia Flowers
- Cactus Dahlias are typically more than 40 inches tall, with long, spiky petals that roll back.
- Decorative Dahlias are 40 inches or taller; their large blossoms have wide, flat-tipped petals.
- Pompon and Ball Dahlias produce flowers in small, perfect spheres of rounded petals.
- Anemone Dahlias feature a “cushion” of tiny disc florets surrounded by a ring of large, flat petals.
- Single Dahlias have flat, overlapping petals and up to 3 rows of bright disc florets.
- Peony Dahlias have open centers, and two or more rows of vivid red petals surrounding a central disc.
How to Grow Dahlia Flowers in Your Garden
There are two ways to start a dahlia growth: from seed, or from tuberous root. When attempting the latter, you must divide the dahlia’s clump of roots so that each tuber has one live bud at its crown. Use a sharp knife to separate the crown, ensuring that you include the bud and at least two sets of leaves.
Growing Dahlias Indoors
- Use well-drained, disease-free soil. Consider buying a soil preparation with vermiculite and peat. You can also use a pasteurized soil-containing medium with shredded peat moss and sand.
- Find a warm environment (70-80 degrees F) away from direct sunlight. Plant the dahlia seeds 1/2-inch deep and add water until the soil is moist. Place a pane of glass over the seed container.
- In 5-7 days, when the first shoots emerge, remove the glass.
Growing Dahlias Outdoors
- Prepare your garden by rototilling 8-10 inches deep. Because dahlias sprout fat roots, they prefer soil with lots of potassium and low nitrogen. Consider using an organic mulch that will preserve moisture while controlling weeds. DO NOT use herbicide.
- After frost season, when the soil is warm, plant dahlia seeds 1/2-inch deep. They thrive in morning sunlight and afternoon shade. Water for 30-60 minutes 3 times a week.
- When the plants reach 3-6 inches tall, begin spraying them with insecticide every week. At 1 foot, tie them to stakes to prevent breakage. When they reach 15 inches, terminal buds will emerge. Remove them to strengthen the dahlia’s growth.
- If you planted the seeds in May, flowers will appear anytime in July.
- Dig the roots out by mid-November; the dahlia’s thin-skinned tubers will rot or freeze in the winter cold.
Dahlia flowers are known for their diversity; they blossom in many different eye-catching shapes and almost every color. In temperate climates, these blooms are easy and rewarding to raise. Their tall stems and wide, vivid flowers would be the star of any garden. However, dahlias’ tuberous roots require a hearty helping of plant food, and will not survive underground after the first frost. They must be protected at all times from moisture-stealing weeds and insects.
With the right amount of moisture and sunshine, dahlias are not hard to please, which is why these flowers have been cultivated and enjoyed for centuries.
Image source: depostiphotos.com.