Dahlias are beautiful flowers and look equally great in the garden or in a flower arrangement. While many people consider Dahlias to be expensive as they run anywhere around $6 - $10 a tuber, they are actually a great investment since they can be divided each year. This can provide you with an endless supply of Dahlias.
Dahlias need to be divided every few years in the spring or fall. If you divide them in the spring the eyes are easier to see but the roots are much harder to cut. Dahlias are tender bulbs, so in many parts of the country, they need to be dug up and stored. Once the plant has been hit by the first frost and dies back it is time to dig them up. Cut the top of the plant down to about 4 to 6 inches and leave the Dahlia in the ground for 10 – 14 days so the plant cures and prepares itself for the winter. This is the time eyes start to develop.
To take the Dahlia out of the ground, dig around a foot away from the plants to loosen the soil. Use a shovel not a fork to do this, so you don’t stab and damage the tuber. With the soil loosened you will be able to lift the Dahlia out of the ground. Shake off the dirt, but be sure to handle the plant gently so you don’t break any tubers off the plant. If you are not ready to divide them, you can store them in a plastic bin or cardboard box with a light layer of soil so the tubers do not dry out and shrivel. Do not seal the lid of the plastic bin and store them in a 40-50 degrees Fahrenheit location.
When you are ready to divide the Dahlias make sure you have sharp pruners and be in a location with bright lighting. The first step is to wash the tubers with high-pressure water from a hose and let them drip dry. The most important thing to learn is to identify an eye on the tuber. The eye is a dark swollen growing node. Depending on the variety, some Dahlias have many eyes and some have only one. If you find one without an eye you can throw it away. In order for the tuber to be viable, the neck must be attached to the tuber.
To start, split the large clump in half with your sharp pruners, which makes the tuber easier to work with. Next, divide each half into individual tubers. It is crucial to make sure each individual tuber has an eye and a neck. If you happen to break a neck of a tuber, just throw it away. The more you do this the easier it will get for you to be familiar with identifying the eyes and to separate the tubers more quickly. After all of the tubers are divided, let them dry completely for a couple of days. When splitting the tubers be sure to label them by variety. You can write the variety name right on the tuber. Also, we suggest you label your storage bins to keep all of the different varieties you grow.
There are several ways you can store the tubers. One is to store the tubers in a plastic or cardboard box. Put 2-inches of peat moss on the bottom of the bin and them place a layer of tubers on top of them. Make sure the tubers do not touch. Then put in another layer of peat moss and add more tubers on top. It is a little like making lasagna. Cover the box but do not seal it as you want to make sure moisture is still allowed in so that the tubers do not shrivel. Check them periodically during the winter to make sure they have not rotted. If one has rotted, throw it away, so it does not contaminate the other tubers.
Another method is to use saran or plastic wrap. This is the recommended method of the American Dahlia Society. Wrap one tuber in the plastic wrap and then put another tuber in the wrap and continue this method until all of the tubers are wrapped. It is like you are making a little snack pack. Make sure the tubers to do not touch. People use this method as it takes up less storage space. It is estimated this method when done properly has a 95% success rate as it keeps the Dahlias moist enough.
With both methods we have mentioned, be sure to store the Dahlia tubers in a 40-50 degrees Fahrenheit location. If the temperature is too high (warm), the tubers will start to wake up and sprout and if the temperature is too cold the tubers will freeze and rot out. Check the tubers periodically and if you see any have rotted out, remove them.
Here is a video that helps you see the eyes and has some other great tips.
Let us know how you make out. If you have any photos of your favorite Dahlias, please share them on our Facebook page.