Dahlias are among the most stunning and versatile flowers that can grace any garden. Known for their vibrant colors, intricate petal patterns, and ability to bloom from summer to fall, these beautiful plants are a favorite among gardeners worldwide. Whether you’re growing dahlias in a small backyard, container garden, or expansive landscape, knowing how to properly divide dahlia tubers is key to ensuring that your plants continue to thrive and multiply year after year.
Dividing dahlia tubers not only helps to rejuvenate your plants but also gives you the opportunity to increase your collection of these beautiful flowers without the need to purchase new plants. The process of dividing dahlia tubers is straightforward and can be done with minimal tools, making it an accessible and rewarding task for gardeners of all experience levels. In this guide, we’ll walk you through the 5 simple steps to divide dahlia tubers successfully and how to care for them throughout the process.
Why Divide Dahlia Tubers?
Before we dive into the step-by-step process, let’s first explore why dividing dahlia tubers is so beneficial.
- Increased Plant Growth: Over time, dahlia tubers can become overcrowded, resulting in smaller flowers and less vigorous growth. By dividing the tubers, you allow each plant more space to grow, leading to healthier plants and larger, more robust blooms.
- Multiplying Your Dahlias: One of the most rewarding aspects of dividing dahlia tubers is that it allows you to grow more dahlias from your existing plants. Each healthy tuber piece has the potential to become a new plant, expanding your garden without the expense of purchasing new plants.
- Promoting Stronger Plants: Dividing dahlia tubers also helps promote stronger, more resilient plants. By removing any damaged or diseased sections and replanting the healthiest parts, you’re setting up your dahlias for success in the next growing season.
- Extending Your Dahlia Collection: If you have a favorite dahlia variety, dividing the tubers is an excellent way to propagate that particular type, ensuring that you can enjoy those blooms for years to come.
Now that we know the benefits, let’s get started on how to divide your dahlia tubers!
Step 1: Wait for Dormancy
The first and most important step in dividing your dahlia tubers is to wait until the plants have gone dormant. Dahlias are not cold-hardy and need to be dug up and stored over the winter in many regions, particularly those with freezing winters.
After your dahlias have finished blooming and the foliage has started to yellow and die back, it’s time to begin preparing for division. Typically, this happens in late fall or early winter, depending on your local climate. The tubers need to be fully mature and dormant before being divided, as doing so too early can damage the plants and prevent successful growth the following season.
Once the plants have died back, leave them in the ground for a couple of weeks, allowing the tubers to fully mature. This gives the plant enough time to store energy in the tubers, which will be critical for their growth the next season.
Step 2: Dig Up the Dahlia Tubers
After the foliage has died back, it’s time to dig up your dahlia tubers. This process should be done carefully to avoid damaging the tubers, which could affect their ability to sprout in the spring.
Steps to dig up the tubers:
- Prepare the Tools: Use a spade, fork, or shovel to carefully dig around the base of the plant. Avoid getting too close to the tubers to prevent unnecessary damage.
- Lift the Tubers: Gently lift the entire root ball out of the ground. If the tubers are large and well-established, they may come out in a clump, while smaller ones may need some additional effort to separate.
- Shake Off Excess Soil: Once the tubers are out of the ground, shake off excess soil to reveal the tubers. Be gentle, as you don’t want to damage the delicate tubers.
- Inspect for Pests or Diseases: Examine the tubers for any signs of pests, rot, or disease. If you notice any unhealthy sections, it’s best to discard them to prevent the spread of infection to the healthy tubers.
At this point, you should have a collection of dahlia tubers that are ready for division.
Step 3: Clean the Tubers
Once you’ve unearthed the tubers, it’s time to clean them before dividing. Cleaning helps to remove dirt, debris, and any remaining remnants of the plant, making it easier to inspect and prepare the tubers for division.
How to clean dahlia tubers:
- Rinse the Tubers: Gently rinse the tubers with water to remove excess dirt. Avoid using harsh tools, as they can damage the tubers.
- Dry the Tubers: After rinsing, place the tubers in a cool, dry area to allow them to air dry completely. This helps to reduce the risk of rot when storing the tubers.
- Trim the Stems: Cut the remaining stems down to about 2-3 inches above the tuber cluster to make the tubers easier to handle and store.
Once the tubers are clean and dry, you’ll be ready to move on to the division process.
Step 4: Divide the Dahlia Tubers
Now comes the most crucial part of the process—dividing the tubers. Dividing your dahlia tubers properly ensures that each piece has the necessary components to grow into a strong, healthy plant.
Steps to divide dahlia tubers:
- Examine the Tubers: Look for natural divisions in the tubers, which often occur around the “eyes” (the growing points). Each healthy division should include at least one eye, as this is where the new plant will sprout from.
- Use Clean Tools: Use a clean, sharp knife or pruning shears to cut the tubers into sections. Each section should have at least one eye and a portion of the tuber for energy storage.
- Remove Damaged Parts: If any tubers appear damaged, diseased, or shriveled, remove those sections entirely. Only divide healthy, firm tubers.
- Allow to Heal: After cutting, allow the divided tubers to air-dry for 24-48 hours. This step helps form a protective callus over the cut surfaces, which reduces the risk of rot when planting.
Step 5: Store or Replant the Divided Tubers
Once the tubers are divided and properly prepared, you have two options: storing the tubers for the winter or replanting them immediately for the next growing season.
To store the tubers for winter:
- Place the tubers in a cool, dry location with good air circulation. You can store them in a cardboard box, paper bag, or a ventilated container.
- Make sure to check the tubers periodically throughout the winter to ensure they are not shriveling or rotting. If any tubers show signs of decay, remove them to protect the healthy ones.
To replant the tubers immediately:
- After dividing, you can replant the tubers in well-draining soil with plenty of sunlight.
- Be sure to space the plants about 18 inches apart to allow room for growth.
If you live in an area with harsh winters, it’s generally best to store the tubers until spring before replanting them.
Conclusion
Dividing dahlia tubers is a simple yet rewarding gardening task that can help revitalize your plants and increase your collection of these stunning flowers. By following these five steps—waiting for dormancy, digging up the tubers, cleaning, dividing, and storing or replanting—you can ensure your dahlias continue to thrive year after year.
Not only will dividing your dahlia tubers result in more plants and vibrant blooms, but it’s also a great way to preserve your favorite varieties and keep your garden flourishing. So, next fall, when your dahlias have finished blooming, don’t forget to divide your tubers and enjoy a beautiful garden for seasons to come.
Happy gardening!