Dahlias are beautiful and deliver brightly colored flowers to your garden. Dahlias are a genus of over 140 species of perennial plants native to Mexico, Central America, and the Southwestern United States. They have been cultivated for more than 200 years and they come in an incredible range of colors, shapes, and sizes. The name Dahlia is derived from the Swedish botanist Anders Dahl, who first described them. Dahlias have been a popular garden plant since they were introduced to Europe by French settlers in 1789.
Dahlias are perennials in zones 8-11. If you live in hardiness zones 2 to 7 you will either treat them like an annual or dig them up and store them in the winter. Most Dahlias grow 4 to 5 feet tall and there are many different types and colors. The flowers can be single or double, with petals coming in every color but black, blue, and green.
Surprisingly, dahlias are easy to grow. They are late-season bloomers and are gorgeous in the garden or as cut flowers. It will take a few stems to make an impressive bouquet. When you cut the flowers, it is good for the plant and causes them to continue to bloom.
Here are some tips that can help you get started growing dahlias:
Tuber Sizing And Eyes
Dahlias are grown from seeds or tubers with tubers being the most popular. The size of the tuber does not necessarily equate to how well the plant will grow or the size of the flower. Tubers come in all sorts of shapes and sizes. Each tuber needs an ‘eye’ to sprout so the plant will grow. The eye is the point at which vegetation growth will begin. Dahlias can be purchased as a single tuber with a bud attached or as a clump of tubers around a stem.
When To Plant Your Tubers
When planting your tubers make sure the soil is warm enough. The general rule is to wait until your soil temperatures are around 60-65 degrees. Dahlias do not like cold temperatures and their foliage is sensitive to frost. In warmer areas, you can start planting them in April in cooler climates it is better to wait. Dahlias also do not like to be wet.
Where To Plant
Dahlias like to be planted in full sun in fertile, well-draining soil. The more sun the better but they can tolerate partial shade. If they are planted in partial shade, you might find the plant grows taller but has fewer flowers. Full shade is to be avoided. You can also plant them in containers. Dahlias grow tall so, select a location protected from the wind.
How To Plant
Dig a hole large enough for the tuber to rest in around 6-8 inches deep. If you have an eye on your tuber, try to point it up and cover the tuber with the soil. If you plan on amending your soil or adding compost, dig the hole deeper. Plant your tubers 9-12 inches apart. Insert stakes when you plant the tubers, it makes it easier to have them there when they are needed in the growing process.
Watering And Care
Do not water your dahlias until you see growth (a sprout). Dahlias can rot with too much water when they are dormant. Make sure your dahlias are not planted in a location that gets too much water. Drainage is particularly important for these plants. If you live in a location that gets a lot of rain, you might lose some plants. Once they start growing, they love to be watered. Consider drip irrigation so the roots get watered, not the foliage.
Once a bloom has finished flowering, it is a good idea to deadhead. This will encourage more buds, and more flowers, and also keep the plant looking nice.
Some people say dahlias are heavy feeders and others say they don’t need anything. To get your dahlias off to a good start make sure the soil is fertile with lots of organic matter. When fertilizing use one with a high percentage of phosphorus, which will promote blooming. Make sure it is not high in nitrogen as this will create great foliage, but few blooms. A recommended fertilizer ratio is 10-30-20. If you plan to dig up your tubers make sure you stop fertilizing at the end of August. If you keep fertilizing your tubers, you are encouraging growth when you should be preparing your tubers for dormancy.
After Blooming Care
Once a frost hits your area the dahlia foliage will die back. The plant will die when there is a freeze. Once this happens, cut back the foliage. If you live in a zone lower than 8, you will want to dig up the tuber for storage. When digging up the tubers make sure you dig deep enough so you don’t damage them. The tuber is porous and can snap easily. Find a location where you can store them either in a garage or basement, where they will not freeze. Dry them out first and then put them in a container or box with peat, pine shavings, or even newspapers. Check on them in the winter. Do not get upset if you lose some when they are in storage.