Overwintering Dahlias: Dahlia Care In Winter

Overwintering dahlias can be a new term for some new gardeners and they may find it a difficult process. But it is not like that at all. The sad part is that in most areas where dahlias are grown, they die in winter. They have to overwinter to save.

Dahlias are doing their best in late summer and fall. At such times, they give abundant flowers and keep the garden alive. Dahlias are famous all over the world for their wonderful flowers. But winter is its enemy and problems start for this flower as soon as this season comes. Basically, dahlias are tender annuals, which means it is not able to withstand the cold of the year. It dies in the first strong frost. Seeing dahlias dying in winter is very sad for all those who are crazy about their flowers.

Back to Main Article   Go back to learn About Dahlia In Detail.

But it is not that dahlias die completely in the winter season all over the world. How dahlias should be treated in winter depends on the hardiness zone in which you are gardening. In the absence of proper knowledge, in order not to harm your dahlias unintentionally, you should have complete information about ‘What to do with your dahlias in winter’ or ‘Overwintering Dahlias’ or ‘Dahlia Care In Winter’. So let’s find out…

What to do with dahlias in winter?

Whenever you want to grow a dahlia flower, you will need tubers for it. So let’s look at the options you have…

The first option is to consider the dahlias in your garden as annuals and leave them as such. Then in the next spring, you can bring a brand new batch of dahlia flowers of your choice and grow flowers from it. This option works well for people who are new to dahlias growing and want to learn more or don’t have the extra time/willingness to overwinter dahlias.

Another option is to overwinter the dahlia tubers in the winter (in other words dig out the tubers and protect them) and grow flowers from them the following summer.

There are many benefits of Overwintering Dahlias…

  1. You can pre-mark the flowers of your choice so that special care can be taken when digging up the tubers and enjoying those flowers again the next spring.
  2. You will know in advance which tubers have performed well this season and will continue to produce healthy plants and beautiful flowers next season.
  3. You will not have to spend money repeatedly to buy new tubers. Rather, you will continue to enjoy flowers from the same tubers for years, as long as you wish.

You might think that overwintering dahlias are a difficult process, but it is not. It is quite simple and easy. All you need to do is follow a few easy, step-by-step instructions. Most experienced gardeners prefer to overwinter the tubers, as they want to produce healthy and strong plants by preserving the best tubers.

To dig dahlia tubers or not?

As mentioned above, there is no need to dig dahlia tubers everywhere. These are warm-season plants. If the winter (first heavy frost) is more than their capacity, then its flowers, leaves, and stem will turn black. Perhaps seeing them, you feel that they are dead, but their tubers are still in good condition. This is because there is still some heat left in the ground. This is the time (or indication) that you have to take some action now.

Hardiness Zones 8-10

If you fall into the category of those less fortunate who live and garden in hardiness zones 8-10, you may not need to do much. This is a hardiness zone where temperatures rarely reach below 20 degrees Fahrenheit. When winter comes, you have to cut the plants 5-8 inches above the soil level and leave them. In the coming spring, a new plant will emerge from that left part of the plant.

Hardiness Zone 7

Dahlias can survive even in this hardiness zone, as long as you take a few steps. It becomes very important for the soil to remain well-drained. For this, you can use a thick layer of mulch to insulate the tubers, so that the heat can be conserved.

If you are susceptible to your dahlias and want to avoid any risks, dig out the tubers and store them indoors.

Hardiness Zones 3-6

If you do gardening in this zone, the only option left for you to save the dahlias is overwintering. You have to dig up dahlia tubers and store them indoors.

For this work, you will need some necessary materials, whose list is given below…

  1. Pruning shears
  2. A shovel or digging fork
  3. Survey tapes
  4. Marker
  5. Damp growing mix
  6. Any one of big nursery pots, black plastic trash bags, or large boxes.

Let’s see how to do it…

How To Overwintering Dahlias? or The right way to dig and store tubers

This is a simple process. But still, to do it successfully, you need to exercise some caution and patience. Have to say that you may find it difficult only the first time.


The first step in the process of overwintering is labeling. This process begins well before winter arrives when you can evaluate the plant and flowers and be sure to mark them. Once winter sets in, good and bad plants look alike, and without labeling it is difficult to identify them. Obviously, you’ll want to preserve for the future those varieties of dahlias you love, healthy plants, and beautiful flowers.

Take a survey tape and write the name on it with the help of a waterproof marker. Then, according to the name, tie it tightly around the base of the plant, which you have chosen to protect.

Prune the plants when winter comes

After the first hard frost, you will see the leaves and stems of the dahlias turning black. Once this happens, leave the plant for a week or two. This helps in hardening the skin of the tuber inside the ground. However, it is not necessary to do this. There is only some convenience in storing hard-skinned tubers.

When the time is right, cut off all plants above 4-5″.

Dig and remove the tuber

Make a circle of about one foot around the stem and start digging. Depending on the size of the plants, you will get the root ball by digging at more or less depth. You may need to dig as deep as 12″ for dwarf varieties of dahlias and about 30″ for larger varieties.

Extra care is required when digging as the tubers can be easily damaged. On the other hand, damaged tubers will not give you the results you want.

Drying the tubers

Allow the dig-out tubers to dry in the open air for a day or two. Keep in mind that there is no direct sunlight or frost on them.

Removal of excess soil

After drying, tubers are usually cleaned and divided. Wash the tubers with water to remove the excess soil.

Subdividing the tubers later

You can leave the dividing process for later if you prefer. Tubers can be divided at any time, even before planting in spring. There will be no need to remove or wash the soil from the tuber clusters if you want to divide later. Store the entire root ball as soon as you dig it out. Read the point below for storage.

Packing tubers

You can pack and store tubers in a number of different ways.

  1. The first way is to store them in a big nursery pot filled with moist soil.
  2. Second, you can store it in a plastic tub or ventilated cardboard box, partially filled with vermiculite or peat moss or damp growing mix.
  3. In the third method, you can take a big black plastic waste bag and store many bunches of tubers together in it. Take special care that the bag is not completely sealed. Tie the bag in such a way that with little movement of air, the moisture remains intact.

Storing tubers

Finally, choose a location that is between 40 and 50 degrees Fahrenheit to store any packaged tubers. It would also be fine to have some moisture and cold at this place.

Caring for stored tubers during winter

Check the tubers periodically throughout the winter for signs of rot or drying out. If this happens then they will not be able to grow further and your hard work will go in vain. If a tuber begins to rot, trim off the rotten part of the bunch so it doesn’t spread.

On the other hand, if the rot has spread to a whole bunch, remove it and continue caring for the other bunch. If the tubers appear shriveled, wash them lightly with water and then keep them in the same box. Dahlia tubers are delicate, so they require a little extra care and caution.

You will have to take care of dahlia tubers like this till the end of winter. Once warm weather arrives, these overwintering tubers can be planted again.

Back to Main Article   Go back to learn About Dahlia In Detail.


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