Introduction
There is nothing quite like the excitement of seeing the first dahlia sprouts emerge in the spring. For many of us, these vibrant blooms are the highlight of the summer garden, offering a spectacular range of colors and shapes. If you have a favorite variety that you wish you had more of, or if you have invested in a rare tuber, learning how to take cuttings is a rewarding way to expand your collection.
At Longfield Gardens, we want to help you make the most of your gardening experience by sharing simple, effective propagation techniques, and our Dahlia Collections make it easy to choose a favorite variety. Taking cuttings is an easy and enjoyable project that allows you to turn one tuber into several healthy, flowering plants. It is a fantastic way to fill your garden with color without a major investment of time or resources.
This guide will walk you through the entire process, from waking up your tubers to successfully rooting your new plants. If you want a big-flowered project to start with, try the Dahlia Dinnerplate High Summer Mix. Whether you are a beginner or a seasoned gardener, you will find that multiplying your dahlias is a straightforward and satisfying task. By following a few basic steps, you can ensure a season filled with even more of the flowers you love.
Why Take Dahlia Cuttings?
Propagating dahlias from cuttings is one of the best-kept secrets of successful flower gardeners. While most people simply plant a single tuber and wait for it to grow, taking cuttings offers several distinct advantages. The same technique works beautifully on Border Dahlias. It is a practical skill that helps you get more value out of every plant you buy.
The primary benefit is the ability to increase your stock quickly. A single healthy dahlia tuber can produce anywhere from five to ten cuttings in a single spring. This means you can transform a small starting kit into a massive, professional-looking flower border in just one season.
Cuttings also tend to grow into very vigorous plants. Because they are "juvenile" growth, they often establish themselves quickly and can sometimes produce flowers earlier than plants grown from tubers alone. Furthermore, plants grown from cuttings produce their own tubers by the end of the season, which you can then dig up and store for the following year.
Finally, taking cuttings is a great insurance policy. If you have a variety that is particularly precious or hard to find, having multiple plants ensures that you won't lose the variety if one plant happens to struggle. If you love a fuller dinnerplate look, the Dahlia Dinnerplate Summer Lovin Collection is another eye-catching option.
Understanding the Dahlia Tuber
To be successful with cuttings, it helps to understand how a dahlia tuber functions. Unlike a potato, which can be cut into many pieces as long as each piece has an "eye," a dahlia tuber only grows from a specific spot. For a closer look at tuber anatomy, see Dahlia Tubers: What You Need to Know. This spot is located on the "neck" or the "crown" of the tuber.
The crown is the area where the tuber meets the old stem from the previous year. This is where the eyes—the small bumps that turn into sprouts—are located. When we take cuttings, we are harvesting these young sprouts as they emerge from the crown.
We work with high-quality growers to ensure the tubers you receive at Longfield Gardens have healthy, viable crowns. Understanding this anatomy is the first step in successful propagation. If you look closely at your tubers in the spring, you will see these small eyes beginning to swell and turn green or purple.
Key Takeaway: Dahlia sprouts only emerge from the crown area. When taking cuttings, focus your attention on the growth appearing at the very top of the tuber, near the old stem.
Essential Materials for Propagation
Before you begin, gather a few basic supplies. Having everything ready will make the process smoother and help ensure your cuttings stay hydrated and healthy. You likely already have most of these items in your gardening shed or kitchen.
- Dahlia Tubers: Start with healthy, firm tubers that show signs of active eyes.
- Growing Medium: A light, sterile potting mix or a blend of peat moss and perlite works best.
- Containers: Shallow trays, open crates, or small 3-inch pots are ideal for waking up tubers and rooting cuttings.
- A Sharp Tool: A clean, sharp craft knife, scalpel, or small paring knife is essential for making clean cuts.
- Rooting Hormone: While not strictly necessary, a liquid or powder rooting hormone can speed up the process and increase your success rate.
- Heat Mat: Providing gentle bottom heat is one of the most effective ways to encourage fast root development.
- Light Source: A bright window or simple shop lights will provide the energy the new plants need to grow.
Step 1: Waking Up Your Tubers
The process of taking cuttings begins indoors, usually about 8 to 10 weeks before your last expected frost date. This gives the tubers enough time to sprout and the cuttings enough time to root and grow before they head outside. If you're not sure when your last frost usually arrives, check the Hardiness Zone Map.
To "wake up" your tubers, place them in a shallow tray filled with slightly damp potting soil. You do not need to bury the entire tuber. In fact, it is better to leave the crown and the neck exposed. This makes it much easier to see the sprouts and make your cuts later on.
Place the tray in a warm spot, ideally between 65°F and 70°F. A heat mat is very helpful during this stage. You don't need much light yet, as the tuber has all the energy it needs to send up its first shoots. Keep the soil barely moist; you want to encourage growth without causing the tuber to rot.
Step 2: Monitoring Growth and Selecting Shoots
Within a week or two, you will see small green or purple nubs appearing on the crown. These will quickly grow into stems with leaves. Patience is important here. You want to wait until the shoots are about 3 to 4 inches tall before you take your first cuttings.
Look for shoots that are sturdy and have at least two sets of leaves. If a shoot is too spindly or very short, let it grow for another few days. The best cuttings are those that look healthy and vigorous. For more season-long advice, see 8 Tips for Growing Better Dahlias.
It is also helpful to observe how many shoots are emerging. If a tuber is producing many sprouts, you can safely take several cuttings. If it only produces one or two, you might want to let one grow to become the main stem of the "mother" plant while taking the other as a cutting.
Step 3: How to Make the Cut
When your sprouts are the right size, it is time to take the cuttings. There are two main ways to do this, and both are very effective. Choose the one that feels most comfortable for you.
The Basal Cutting Method
This is the most popular method because it often results in faster rooting. Using your sharp knife, cut the shoot at the very base where it meets the tuber. Try to take a tiny "heel" or sliver of the tuber skin with the shoot. This area is rich in growth hormones and will help the cutting root quickly.
The Stem Cutting Method
If you don't want to risk nicking the tuber, you can simply cut the shoot just above the lowest set of leaves (the "nodes"). Leave the bottom set of leaves on the tuber. This method is great because the remaining part of the stem on the tuber will often branch out and produce even more shoots for you to harvest later.
Regardless of the method you choose, always use a clean knife. If you want to explore the bloom forms mentioned here, read How to Grow Dinnerplate Dahlias. We recommend wiping your blade with rubbing alcohol between different dahlia varieties to keep your plants healthy and prevent the spread of any potential issues.
What to do next:
- Identify a shoot that is 3-4 inches tall with two sets of leaves.
- Use a sterile blade to cut the shoot at the base.
- Immediately move to the preparation and planting phase to prevent wilting.
Step 4: Preparing the Cutting for Planting
Once you have removed the shoot, you need to prepare it for its new life as an independent plant. This part of the process is quick but requires a gentle touch.
First, remove the bottom set of leaves. You want a clear section of stem that can be inserted into the soil. If the remaining leaves at the top are very large, you can trim them in half with your scissors. This reduces the amount of water the cutting loses through its leaves while it is trying to grow roots.
Next, dip the bottom of the stem into your rooting hormone. If you are using a liquid hormone, a 5-second dip is usually plenty. If using a powder, gently tap off the excess. This step provides a little extra "encouragement" for the plant to start forming roots.
Step 5: Planting and Rooting Environment
Now it is time to give your cutting a home. Use a pencil or a small stick to poke a hole in a pot filled with moist, sterile potting mix. Inserting the cutting into a pre-made hole prevents the rooting hormone from being rubbed off as you push the stem into the soil.
Firm the soil gently around the base of the cutting to ensure good contact. This is vital because the stem needs to draw moisture from the soil immediately.
Creating a Humidity Dome
Cuttings do not have roots yet, so they cannot drink water from the soil very well. They need a humid environment to keep their leaves from wilting. You can use a clear plastic dome, a plastic bag held up with sticks, or even a clear plastic cup flipped upside down over the pot.
The Importance of Heat and Light
Place your newly planted cuttings on a heat mat. Bottom heat is the "magic ingredient" for rooting dahlias. Aim to keep the soil temperature around 70°F.
For light, a fluorescent or LED shop light kept a few inches above the cuttings for 14 to 16 hours a day is perfect. Dahlias are sensitive to day length; giving them long "days" of light tells the plant to focus on growing roots and leaves rather than trying to form a tiny tuber too early. For a ready-made cutting-garden option, the Dahlia Decorative Summer Jewels Mix is a good example.
Step 6: Caring for Your Young Cuttings
For the next two to three weeks, your main job is to monitor the moisture and humidity. Check the pots daily. The soil should be damp like a wrung-out sponge, but never soggy. If you see a lot of condensation inside your humidity dome, prop it open for an hour to let some fresh air in.
You will know your cuttings have rooted when you see new green growth appearing at the top. Another way to check is to give the cutting a very gentle tug. If you feel resistance, it means roots have taken hold in the soil.
Once the plants are rooted, you can remove the humidity dome. At this stage, you can also begin a very light feeding schedule. Use a balanced, water-soluble fertilizer diluted to half-strength once a week to give the young plants the nutrients they need to grow strong stems.
Key Takeaway: Consistent warmth and high humidity are the most important factors during the first 14 days. Once you see new leaves, your cutting has officially become a new dahlia plant.
Hardening Off and Moving Outdoors
As the weather warms and the danger of frost passes, your cuttings will be ready to move to their permanent home in the garden. However, they have lived a very pampered life indoors, so they need a transition period called "hardening off."
Start by moving your plants outdoors to a sheltered, shady spot for an hour or two a day. Gradually increase their time outside and their exposure to sunlight over the course of 7 to 10 days. This toughens up the leaves and prepares them for the wind and sun of the open garden.
When you are ready to plant, treat them just like any other dahlia. Choose a spot with at least 6 to 8 hours of direct sunlight and well-draining soil. Because these plants are already growing, they will often take off very quickly once they hit the warm garden soil. For planting details, read How to Plant and Grow Dahlia Tubers.
Managing the Mother Tuber
While you are busy with your cuttings, don't forget about the original tuber! After you have taken all the cuttings you want, you can still plant the mother tuber in your garden.
Even if you have cut away many of the initial sprouts, the tuber will continue to produce new eyes. It is a very resilient system. Simply plant the tuber at the normal depth (about 4 to 6 inches deep) once the soil has warmed up to 60°F. You will end up with the original plant plus all the new clones you created from the cuttings. If you want a refresher on fall cleanup, see How Do I Store Dahlia Tubers.
At Longfield Gardens, we have found that this "tuber plus cuttings" approach is the most effective way to create a lush, flower-filled landscape in a single season. It allows you to maximize the potential of every variety you grow.
Simple Troubleshooting for Success
While taking cuttings is generally a high-success activity, you might run into a few common situations. If you want extra reassurance, Longfield Gardens' 100% Quality Guarantee stands behind the tubers you buy.
- Wilting: If your cuttings are drooping, they likely need more humidity. Ensure your humidity dome is sealed well and mist the leaves lightly with water.
- Damping Off: If the stem turns black at the soil line, the soil is likely too wet or the air is too stagnant. Use a sterile potting mix and ensure there is a little air circulation.
- No Roots After Three Weeks: This is often caused by temperatures being too cool. Check that your heat mat is functioning and that the area is not drafty.
- Yellowing Leaves: This can be a sign that the plant has used up the energy in the stem and needs a very light dose of fertilizer.
Remember, gardening is a learning process. If a cutting doesn't take, don't worry—your mother tuber will likely produce another sprout that you can try again with in a few days.
What to do next:
- Check soil moisture daily.
- Ensure the heat mat remains consistent.
- Watch for new leaf growth as a sign of success.
- Begin hardening off only after the plant is robust and the weather is stable.
Expected Results and Timeline
When you take cuttings, it is helpful to have a general idea of the timeline. While every garden and microclimate is different, most dahlia cuttings follow a predictable path:
- Weeks 1-2: Tubers wake up and sprouts emerge.
- Weeks 2-3: Shoots reach 3-4 inches; cuttings are taken and planted.
- Weeks 4-6: Cuttings develop a strong root system.
- Weeks 6-8: Young plants are potted up or begin the hardening-off process.
- Weeks 10+: Plants are moved to the garden and begin rapid summer growth.
By mid-summer, your cuttings will likely be indistinguishable from your tuber-grown plants. They will bloom beautifully and, most importantly, they will spend the summer forming their own brand-new tubers underground. When you dig them up in the fall, you will have even more tubers to store for next year!
Conclusion
Taking cuttings from dahlia tubers is a simple, joyful way to multiply the beauty in your garden. It transforms the way you think about your plants, moving from a single flower to an entire collection of clones that will brighten your landscape. If you want another ready-made mix for future plantings, the Dahlia Assorted Enchantment Collection offers a vibrant mix for borders, bouquets, and showy garden beds.
At Longfield Gardens, we stand behind the quality of our tubers and want you to have the best possible results. Whether you are growing a giant Dinnerplate variety or a delicate border dahlia, these propagation steps will help you fill your garden with color. Remember to start with clean tools, provide plenty of warmth, and keep the humidity high for the best results.
- Start your tubers indoors 8-10 weeks before the last frost.
- Take cuttings when shoots are 3-4 inches tall.
- Use bottom heat and high humidity to encourage rooting.
- Harden off plants gradually before moving them to the garden.
We are here to support your gardening journey every step of the way. With a little bit of patience and these straightforward steps, you can easily grow a stunning dahlia garden that brings joy all season long.
FAQ
How long does it take for a dahlia cutting to grow roots?
Under ideal conditions with bottom heat and high humidity, most dahlia cuttings will develop roots within 10 to 21 days. You will know they have rooted when you see new green growth appearing at the top of the plant or when the cutting resists a very gentle tug.
Do I need rooting hormone to grow dahlias from cuttings?
While rooting hormone is not strictly required, it is highly recommended because it significantly increases the success rate and speeds up root development. If you prefer not to use it, ensure your cuttings have plenty of bottom heat and humidity to compensate.
Can I take cuttings from a dahlia plant growing in the garden?
Yes, you can take cuttings from garden plants during the summer, but they can be slightly more difficult to root than early spring basal cuttings. Ensure the summer cuttings are taken from non-flowering side shoots and kept very cool and hydrated until they form roots.
Will a plant grown from a cutting produce tubers for next year?
Yes, dahlia cuttings are very productive and will grow a completely new cluster of tubers underground during their first growing season. You can dig, divide, and store these tubers in the fall just like you would with a plant grown directly from a tuber.
