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How To Prune Dahlias? Effective Tips to Start Pruning Today

How to prune dahlias

Suppose you want to open a flower shop and are not sure which flowers to stock. Let me save you the trouble of choosing from many different flowering plants — just plant different cultivars of dahlia and your shop would be set. Dahlia is a beautiful flowering plant that blooms in many different colors except blue and true yellow. It has beautiful big blooms that are a treat for eyes. Flowers of dahlia bloom on long stems that make it perfect for cutting arrangements. However, you won’t get those amazing beautiful blooms just by sitting around. Dahlia’s need proper pruning for bigger flowers. If dahlia’s are not pruned, they can become top-heavy and will only produce small flowers.  

You might be wondering, how does pruning exactly benefit your dahlia flowers? First off, let’s start by answering what pruning is exactly. Pruning is a practice that has been done since antiquity, and it involves trimming some branches, buds, leaves, or roots. While it may seem unproductive to trim those parts of the plant, at first sight, it is actually for the benefit of the plant. It involves pruning the parts of the plant that are sickly, dead, or those that have mold in them. This action is necessary to avoid the spread of the disease throughout your entire plant.

Pruning is not only for health though, but it can also be for encouraging growth. There may be some parts of the plant that are unnecessary for helping a plant bloom or produce fruits. In circumstances like those, they are trimmed off as well, healthy or not, so that the plant may direct its energy resources to focus on its blooming or growth instead. These pruning practices will greatly benefit your dahlias if properly applied.

When pruning your dahlia’s, a few things need to be considered. If proper pruning technique is not followed, your pruning effort will not only go to waste but it can also hurt the plant. But, you don’t have to worry about that. We have compiled this ‘how to prune dahlia’ guide to walk you through the steps of pruning your dahlia, to make sure that you can get the best dahlia flowers throughout the season.

StepWise Guide for Pruning Dahlia

Clean the Shears

Get those pruning shears out of the cupboard because we’ve got work to do. But before you go, make sure that your shears are clean. So why bother cleaning them? Dirty pruning shears are like firing a gun in the opposite direction. Diseases and infections can easily transfer to your dahlia and you can even lose your plant. It’s best to at least wipe the shears with a disinfectant before heading into the garden. This is especially much more important when you are cutting from stem to stem.

When to Prune Dahlia?

Dahlia should be pruned at the start of their growth when they are 12 to 16 inches tall, and after they have bloomed. Light pruning throughout the season for removing damaged and diseased parts are also encouraged. Finally, the stems are cut back to about 2 to 3 inches from the ground after the first frost for overwintering. More on this later.

How to Care for Dahlias? Steps for Pruning Dahlia

1) Topping

How To Prune Dahlias

As soon as your dahlia grows to about 12 inches tall — it’s time to prune. Cut the top of the plant above the fourth leaflet. This would shift the energy of the plant towards root and foliage formation instead of flowers. Don’t get me wrong, we do want flowers for our plant, rather we only want the best flowers, so by giving up on the initial growth, we stimulate the plant to grow bushier. This increases the strength of the plant and it produces more blooms in the future. 

Don’t be afraid to prune your dahlia as they will recover quickly at this phase of the plant’s growth. 

2) Disbudding Dahlia: Pinching off the Additional Buds

Don’t let more than 3 to 5 buds to remain on the plant. It may sound counterintuitive to pinch off the flowering buds when we want to get more flowers, but being greedy can cost you. By keeping the buds to a small number, we are ensuring that the flowers have enough energy to grow to a full size. If we let all the buds to bloom, it will leave us with many small flowers that won’t be nearly as captivating as the full blooms. Usually, there are 3 to 4 buds on each stem–one on the end and others on the sides. We need to keep the bud on the end and remove the lateral buds. This process of removing additional buds is known as disbudding dahlia.

On the other hand, if you don’t mind a dahlia plant that is small but has many flowers in one plant, then you may allow the stems to grow on their own. You may notice that as much as 10 flowers may grow in a dahlia plant. This really is personal preference so the choice is yours.

3) Remove Damaged flowers and leaves

Whenever the question of how to care for dahlias is asked, removing damaged parts is a fundamental step. If you see any flower with spots and wet texture, it is a sign of a fungal attack. It’s best to prune that flower off as the infection can spread to other parts of the plant. The same goes for the damaged leaves. Damaged leaves usually have a yellowish color.

4) Deadheading

Your flowers have grown to the fullest and now, like all good things, they are withering away. What if I told you that you can get your dahlia to rebloom before the end of the season? To achieve this, you need to deadhead you dahlia after they have withered or are reaching their end. To do this, just cut off the withered flowers all the way back to where they attach to other buds on the main stem. By doing this, the plant tries to flower again for the production of the seeds and you get to enjoy the blooms once again.

5) Overwintering

The winter is here and your blooms are gone. To get the most exuberant blooms in the next season, you need to decide how you would overwinter your dahlia. Dahlias are usually taken as an annual but they can be overwintered easily. After the first frost, cut back the plant to about 2-3 inches from the ground. Dahlias have tubers beneath the plant which are responsible for the new growth. Now there are two options: either dig up the tubers and store them in a dry, frost-free place or let them remain in the ground. If the soil is well-drained and the frost won’t reach the tubers, you can leave them in the ground. However, if there is a danger of frost reaching the tubers, it’s best to dig the tubers and store them inside till the spring. The simple process for storing and drying tubers is as follows:

  1. Dig up the tubers carefully without damaging it.
  2. Allow them to dry in a frost-free location without exposing it to direct sunlight.
  3. Remove the soil covering from the tuber. 
  4. Store in a ventilated box with slightly moistened sand at a temperature of 45-55 degrees F.
  5. Check the tubers periodically for any signs of rot or dryness. If they appear dry, sprinkle little water, and if they are starting to rot, cut the rotted portion to protect the remaining plant.

Replant these dried tubers in the spring.

Steps for Pruning Dahlias in Pots

The Steps for pruning dahlias in pots are almost the same with a little adjustment. 

  1. When topping the potted dahlias, you should cut the top of the stem just above the first set of leaves when the plant has grown 3 sets to make the plant bushier.
  2. Pinch off the bottom two pairs of leaves when the plant becomes 2 ft tall to improve air circulation.
  3. Deadhead the spent flowers after they fade like with outdoor plants.
  4. Dig up the tubers after several touches of frost and store them using the process explained


Dahlias are an outstanding plant with beautiful flowers. They perform best when provided with adequate sunlight. Pruning helps to increase the size of the flowers as well as the strength of the plant. By topping the plant early on, the plant develops a strong root system with sturdy stems which can support more blooms during the season. Deadheading the plant after the flowers wither encourage the plant to rebloom. Though they are treated as annuals, by storing the tubers in a ventilated, dry, and frost-free place, they can easily be overwintered.

Pruning seems tough at first but once you dive into it, it’s kind of fun. It’s like taking care of your pet–you need to do it regularly. This guide on how to prune dahlias will help you out a lot. 

Good Luck!

Now that you have learned how to prune a dahlia, do you have any thoughts or tips you would like to share? Or any question perhaps? Comment below! Our website also offers other guides as well such as How To Prune Rose Of Sharon and How To Prune Grape Vine.

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