Do Bedding Dahlias Have Tubers?

Table of Contents

1. Introduction
2. Understanding Bedding Dahlias
3. The Secret Underground: How Tubers Form
4. Should You Save Bedding Dahlia Tubers?
5. How to Harvest and Store Bedding Dahlia Tubers
6. Caring for Bedding Dahlias During the Season
7. Growing Bedding Dahlias from Seed
8. Common Myths About Bedding Dahlia Tubers
9. Realistic Expectations for Your Garden
10. Why We Love Bedding Dahlias
11. Conclusion
12. FAQ

Introduction

If you have ever tucked a flat of colorful bedding dahlias into your garden borders or porch containers, you know the instant joy they bring. These compact plants are famous for their prolific blooms and tidy habit, offering a splash of color that lasts from early summer right until the first frost. At Longfield Gardens, we believe these smaller varieties are one of the best ways to enjoy the beauty of dahlias without the need for the heavy staking or large garden footprints required by their taller cousins.

Many gardeners encounter bedding dahlias as small potted plants at a local nursery or grow them from a packet of seeds. Because they start so small, a common question arises at the end of the season: do bedding dahlias have tubers? It can feel like a bit of a garden mystery when you go to pull up your "annual" flowers and find something substantial hiding beneath the soil. You can also browse our Dahlia Collections for more compact and colorful options.

In this guide, we will answer that question directly and explain how you can manage these hidden treasures. Whether you want to treat your bedding dahlias as one-season stars or keep them for years to come, understanding their lifecycle is the key to a successful garden. We will cover the biology of these plants, how to store their tubers, and how to keep them blooming beautifully all summer long. For a broader overview, see our All About Dahlias guide.

Bedding dahlias absolutely do grow tubers, and once you know they are there, a whole new world of perennial gardening opens up to you.

Understanding Bedding Dahlias

To understand why people often wonder about their root systems, it helps to define what exactly a bedding dahlia is. In the world of gardening, "bedding" is a term used for plants that stay relatively short—usually between 8 and 20 inches tall. Unlike the giant dinnerplate dahlias that can reach five feet in height, bedding varieties are bred for a compact, bushy shape. They are perfect for the front of a flower bed, window boxes, or decorative pots.

These plants are often sold alongside pansies and petunias in the spring. Because of this, many people assume they are strictly annuals that die off completely when the cold weather hits. However, bedding dahlias are still members of the same family as the large exhibition types. This means their biology is built to survive through specialized underground storage organs.

Even if you started your dahlias from a tiny seed in March, by October, that plant has been busy working underground. While you were enjoying the flowers, the plant was sending energy down into its roots to prepare for the future.

The Secret Underground: How Tubers Form

The short answer is yes: bedding dahlias do have tubers. If you were to dig up a healthy bedding dahlia in the late autumn, you would likely find a cluster of small, sausage-shaped structures attached to the base of the stem. These are the tubers.

Think of a dahlia tuber as a biological battery. Throughout the summer, the leaves of the plant soak up sunlight and turn it into energy through photosynthesis. The plant uses some of that energy to produce those beautiful flowers we love, but it also saves a portion for later. It sends this surplus energy down into its root system, where it swells into thickened, starchy tubers.

Why Do They Make Tubers?

In their native habitats of Mexico and Central America, dahlias use these tubers to survive periods of dormancy. When the weather gets too dry or too cold for the foliage to survive, the plant "sleeps." The energy stored in the tubers allows the plant to push out brand-new growth as soon as favorable conditions return.

Even though we often grow them in different climates, the plant's internal clock remains the same. It is hard-wired to build a storage system.

Tubers from Seed vs. Tubers from Roots

One reason for the confusion about bedding dahlia tubers is the way they are propagated.

• Tuber-grown dahlias: Most large dahlias are sold as dormant tubers. You plant a tuber, and it grows into a clone of the parent plant.
• Seed-grown dahlias: Many bedding varieties, such as the "Mignon" or "Figaro" mixes, are grown from seed.

When you plant a dahlia seed, it starts with a standard, thin root system. However, as the seedling matures and reaches its full flowering potential, it begins the process of tuberous development. By the end of its first growing season, even a seed-grown dahlia will have developed a modest clump of tubers.

Key Takeaway: Every dahlia, regardless of whether it is a tall variety or a short bedding type, is a tuberous perennial. If the plant is healthy and has a full growing season, it will create tubers.

Should You Save Bedding Dahlia Tubers?

Just because bedding dahlias produce tubers doesn't mean you must save them. At Longfield Gardens, we find that gardeners usually fall into two camps when it comes to these compact beauties.

Treating Them as Annuals

Many gardeners prefer the convenience of treating bedding dahlias as annuals. Since seed-grown bedding dahlias are relatively inexpensive and grow very quickly, it is often easier to simply pull them up at the end of the year and start fresh with new colors the following spring. This approach is great if you like to change your garden's color palette every year or if you don't have a cool, frost-free place to store tubers over the winter.

Treating Them as Perennials

If you find a specific bedding dahlia with a color or flower shape that you absolutely adore, saving the tubers is a wonderful "easy win." Saving the tubers ensures that you will have the exact same plant next year. Furthermore, a plant grown from a saved tuber often has a bit of a head start in the spring compared to one grown from a tiny seed, leading to earlier blooms.

If you decide to save them, keep in mind that bedding dahlia tubers are typically smaller and more delicate than those of larger varieties. They require a gentle touch during the digging and storage process.

How to Harvest and Store Bedding Dahlia Tubers

If you have decided to keep your bedding dahlias for next year, the process is very similar to saving larger dahlia varieties. For a step-by-step refresher, see our How to Lift and Store Dahlia Bulbs.

Step 1: Wait for the Frost

The best time to dig up your tubers is after the first frost has "blackened" the foliage. This frost tells the plant that the season is over and it is time to move all remaining energy into the tubers. After the foliage turns brown or black, cut the stems down to about three or four inches above the soil line.

Wait about a week after cutting the stems before you dig. This short waiting period allows the tubers to "cure" slightly in the ground, which can help toughen the skin for storage.

Step 2: Dig Carefully

Because bedding dahlia tubers are small, they are easy to snap or damage. Use a garden fork rather than a sharp spade if possible.

• Start digging about 8 to 10 inches away from the main stem.
• Gently pry upward from several sides to loosen the soil.
• Lift the entire clump of soil and tubers together.

Step 3: Clean and Dry

Gently shake off the excess soil. You can use your fingers to brush away large clumps, but avoid scrubbing the tubers. You don't need to wash them with a hose unless your soil is very heavy clay. If you do wash them, make sure they dry completely in a shaded, well-ventilated area for 24 hours before storing. Excess moisture is the primary cause of rot during the winter.

Step 4: The Packing Process

Bedding dahlia tubers can dry out (shrivel) faster than larger tubers because they have less mass. To prevent this, we recommend packing them in a breathable material.

• Place the tubers in a cardboard box or a plastic bin with holes for ventilation.
• Cover them with slightly damp peat moss, vermiculite, or pine wood shavings.
• Ensure the tubers are not touching each other to prevent any potential rot from spreading.

Step 5: Finding the Right Spot

Store your box in a cool, dark place that stays between 40°F and 50°F. An unheated basement, a crawl space, or a cool closet in a garage (as long as it doesn't freeze) works well. Check them once a month. If they look shriveled, mist the packing material slightly with water. If you see any soft or moldy spots, remove those tubers immediately.

What to do next:

• Label your tubers with the color and height before storing.
• Choose a storage container that allows for some air circulation.
• Check the temperature of your storage area with a thermometer to ensure it stays above freezing.
• Set a recurring reminder on your phone to check the tubers once a month.

Caring for Bedding Dahlias During the Season

To ensure your bedding dahlias actually produce healthy tubers for next year, they need the right care throughout the summer. A stressed plant will put its energy into survival rather than storage.

Sunlight and Soil

The "right plant, right place" rule is essential here. Dahlias are sun-lovers. To get the best blooms and the strongest tubers, ensure they receive at least 6 to 8 hours of direct sunlight daily. They also require "good drainage," which simply means water should move through the soil easily rather than sitting in a puddle. If you are planting in containers, make sure there are plenty of drainage holes at the bottom. For more container-specific advice, see our How to Grow Border Dahlias.

Water Correctly, Not Constantly

When you first plant your dahlias (whether from seed, a small pot, or a saved tuber), water them once and then wait. Over-watering before the plant has a strong root system can cause the tuber to rot. Once the plant is about six inches tall and growing vigorously, you can begin a regular watering schedule.

We recommend watering deeply once or twice a week rather than giving them a light sprinkle every day. This encourages the roots to grow deeper into the soil, making the plant more resilient and helping the tubers develop more robustly.

The Power of Pinching

One of the best "pro tips" for bedding dahlias is to pinch them. When the plant is about 8 to 12 inches tall, snip off the very top of the center stem. This might feel like you are hurting the plant, but it actually signals the dahlia to grow side branches. This results in a bushier plant with significantly more flowers. More leaves and more flowers mean more energy being produced and stored in those underground tubers. For a quick how-to, see our How to Pinch and Stake Dahlias.

Feed for Flowers

Dahlias are "heavy feeders," meaning they appreciate a bit of extra nutrition. However, avoid fertilizers that are very high in nitrogen. Nitrogen promotes lots of green leaves but can result in weak stems and fewer flowers. Look for a fertilizer where the second and third numbers (phosphorus and potassium) are higher than the first. This supports flower production and tuber health.

Growing Bedding Dahlias from Seed

If you enjoy the process of starting plants from scratch, growing bedding dahlias from seed is an incredibly rewarding and affordable project. While you won't know exactly what the tubers look like until the fall, the process of getting there is simple.

1. Start Early: Sow seeds indoors about 4 to 6 weeks before your last expected frost date.
2. Use Seed Starting Mix: A light, fluffy soil mix helps the tiny roots grow without resistance.
3. Provide Light: Once the seeds sprout, they need a lot of light to keep from getting "leggy" (tall and weak). A sunny windowsill or a simple shop light works perfectly.
4. Hardening Off: Before moving them outside, gradually introduce them to the wind and sun over the course of a week.

The most exciting part of growing from seed is the variation. Even in a single packet of seeds, you might get a range of colors, from bright yellows to deep purples. If one particular seedling produces a flower you love, you can dig up its tubers in the fall and have that exact plant again next year!

Common Myths About Bedding Dahlia Tubers

Because these plants are so often treated as disposable annuals, several myths have circulated among gardeners. Let’s clear those up with some simple facts.

Myth 1: "Seed-grown dahlias don't make tubers in their first year." As we've discussed, this is false. While the tubers may be smaller than those from a multi-year-old plant, they will definitely be there by the time the first frost hits.

Myth 2: "Bedding dahlia tubers are too small to survive the winter." While they are smaller, they are just as hardy as large tubers. The key is preventing them from drying out completely. Because they have less surface area, they can lose moisture quickly, which is why storing them in peat moss or wood shavings is so important.

Myth 3: "You can't divide bedding dahlia tubers." You actually can! If a bedding dahlia clump grows large enough over a couple of seasons, you can divide it just like any other dahlia. Just make sure each division has an "eye"—the small bump where the new growth will emerge.

Realistic Expectations for Your Garden

Gardening is a rewarding activity, but it is also a partnership with nature. It is important to remember that weather, soil quality, and even your local microclimate will affect how your bedding dahlias grow.

In very hot climates, bedding dahlias might take a "break" from blooming during the peak of summer heat. Don't worry—this is normal. Keep them watered, and they will usually provide a second, even more spectacular show once the evening temperatures begin to drop in late August.

Similarly, the size of the tubers you find in the fall can vary. A plant grown in a small pot on a balcony might produce smaller tubers than one grown in rich, fertile garden soil. Both are capable of growing again next year, provided they are stored with care.

"A bedding dahlia's size above the ground doesn't always reflect its strength below the ground. Even a small, 12-inch plant can produce a vigorous cluster of tubers ready for next season."

Why We Love Bedding Dahlias

At Longfield Gardens, we appreciate bedding dahlias for their versatility. They bridge the gap between high-maintenance floral stars and easy-going landscape plants. They offer the intricate beauty of a dahlia bloom on a plant that fits into almost any space.

Knowing that these plants have tubers gives you more choices as a gardener. You have the freedom to treat them as a seasonal treat or to build a collection of favorite varieties that return year after year. To compare more styles and sizes, explore our Other Dahlias. This flexibility is what makes gardening such an accessible and enjoyable hobby for everyone, from beginners with a few pots to experienced growers with large borders.

Conclusion

Bedding dahlias are far more than just temporary annuals. These compact powerhouses work hard all summer long to develop a system of underground tubers, ensuring they have the energy to grow again. Whether you started your plants from seed or bought them as small starts, you will find those "hidden batteries" waiting for you in the soil at the end of the season.

By following a few simple steps—providing plenty of sun, watering deeply, and storing the tubers in a cool, dry place—you can enjoy these beautiful flowers for many years. Gardening should be a rewarding journey, and discovering the hidden tubers of your bedding dahlias is just one of the many "easy wins" you'll find along the way.

Final Takeaways for Bedding Dahlia Success:

• Yes, they have tubers: All bedding dahlias develop tubers by the end of the season.
• Sun is key: 6–8 hours of direct light ensures healthy tuber development.
• Pinching pays off: Snip the tops early for a bushier plant and more blooms.
• Storage is simple: Use breathable material like peat moss to keep tubers hydrated but rot-free over winter.

We invite you to explore the wonderful world of dahlias and see just how much beauty these compact plants can add to your home. To find your next favorite garden addition, feel free to browse our New Dahlias Tubers.

FAQ

Can I leave bedding dahlia tubers in the ground over winter?

This depends entirely on your USDA hardiness zone. If you live in Zone 8 or warmer, you can often leave your tubers in the ground if you provide a thick layer of mulch to protect them from occasional dips in temperature. However, in Zone 7 or colder, the ground will freeze deep enough to kill the tubers, so they must be dug up and stored indoors.

Do seed-grown bedding dahlias come back the same color from tubers?

Yes! When you grow a dahlia from a tuber, you are essentially growing a clone of the plant from the previous year. While the seeds themselves will produce plants with a variety of colors and shapes, the tuber that forms under a specific plant will always produce that same flower. This is the best way to preserve a specific color you love from a seed mix.

How big should the tubers be before I save them?

There is no minimum size for a dahlia tuber to be viable. As long as the tuber is firm, healthy, and attached to a piece of the "crown" (the area where the stem meets the roots) that has an eye, it can grow a new plant. Bedding dahlia tubers are naturally smaller than those of dinnerplate varieties, so don't be discouraged if they look like small fingerling potatoes.

When should I replant my bedding dahlia tubers in the spring?

Patience is important here. Wait until the soil temperature reaches about 60°F and all danger of frost has passed. Planting too early into cold, wet soil can cause the tubers to rot before they have a chance to sprout. For help with timing, see our How to Plant Dahlia Bulbs for a Vibrant Summer Garden.