Table of Contents
- Introduction
- Understanding Pom Pom Dahlias
- Choosing the Perfect Planting Site
- When to Plant Your Dahlias
- How to Plant Pom Pom Dahlia Tubers
- The Most Important Rule: Do Not Water Yet
- Caring for Your Growing Plants
- Managing Pests and Challenges
- Harvesting and Deadheading
- Season's End: What to Do in the Fall
- Growing Pom Pom Dahlias in Containers
- Summary of Success
- FAQ
Introduction
There is a unique sense of wonder that comes with seeing the first bloom in your garden. These perfectly spherical, honeycomb-textured pom pom dahlias look almost too precise to be real, yet they are among the most rewarding and productive plants you can grow. At Longfield Gardens, we love these petite powerhouses because they add a sophisticated, architectural element to flower beds and summer bouquets alike.
Whether you are a beginner or a seasoned gardener looking to add more variety to your landscape, dahlias are a fantastic choice. This guide will walk you through everything you need to know about growing these charming flowers, from selecting the right spot to harvesting stems for your home. We want to help you feel confident as you start your dahlia-growing journey this season.
With the right preparation and a few simple care steps, you can enjoy a massive display of blooms from midsummer all the way until the first frost.
Understanding Pom Pom Dahlias
Before you dig your first hole, it helps to know exactly what makes a pom pom dahlia unique. In the world of dahlias, there are many different classifications based on flower shape and size. Pom pom dahlias (sometimes spelled "pompon") are defined by their petite, globe-shaped blooms.
To be classified as a true pom pom, the flower must be a double bloom that is less than two inches in diameter. The petals, or florets, are blunt or rounded and curve inward for their entire length. This creates a tight, spiral pattern that looks like a miniature work of art.
You might also see "ball" dahlias. These are very similar in shape but are larger, usually ranging from two to four inches across. Because their care requirements are identical, many gardeners grow them side-by-side. Varieties like 'Franz Kafka' and 'Moor Place' are classic examples of pom pom dahlias that offer incredible color and form.
Choosing the Perfect Planting Site
Success with dahlias starts with picking the right location. Like most summer-blooming tubers, pom pom dahlias have a few non-negotiable needs to perform their best.
Prioritize Sunlight
Dahlias are sun-loving plants. For the most abundant flowers and the strongest stems, choose a spot that receives at least six to eight hours of direct sunlight every day. While they can grow in partial shade, they will often become "leggy" as they stretch toward the light, and you will see fewer blooms.
In exceptionally hot climates, such as the southern United States, your plants may appreciate a bit of afternoon shade. This prevents the delicate petals from scorching during the most intense heat of the day.
Check Your Soil Drainage
Drainage is perhaps the most important factor in keeping your tubers healthy. "Drainage" simply means how fast water leaves the soil after a rain or watering. Dahlias do not like "wet feet," which can cause the tubers to soften or rot before they even start growing.
If you have heavy clay soil, you can improve the structure by mixing in compost or aged manure. This adds organic matter that helps water move through more freely. If your garden has a spot where puddles linger for hours after a storm, it is best to choose a different location or consider planting in raised beds or containers.
Provide Enough Space
While pom pom dahlias produce small flowers, the plants themselves can grow quite large. Most varieties reach a height of three to four feet and a width of about two feet. Proper spacing ensures that air can circulate around the foliage, which helps keep the plants healthy and prevents common issues like powdery mildew.
Key Takeaway: Choose a sunny, well-draining spot and plan to space your pom pom dahlias about 12 to 18 inches apart to give them room to shine.
When to Plant Your Dahlias
Timing is everything when it comes to planting dahlia tubers. Because they are native to the warm climates of Mexico and Central America, they have no tolerance for frost or cold soil.
The best time to plant is in the spring, once the threat of frost has completely passed. However, the air temperature is only half the story. You should also wait until the soil has warmed to about 60°F. If you plant into cold, wet soil, the tuber will sit dormant and may struggle to establish.
In most parts of the US, this planting window opens between late April and early June. If you want to get a head start, you can "start" your tubers indoors in pots about four weeks before your last frost date. Place them in a warm, sunny window or under grow lights, then transplant the established plants into the garden once the weather is consistently warm.
How to Plant Pom Pom Dahlia Tubers
Planting a dahlia tuber is a simple process, but getting the orientation and depth right will help the plant emerge more quickly.
Step 1: Dig the Hole
Dig a hole about four to six inches deep. If you are planting multiple tubers, you can dig individual holes or one long trench. At this stage, it is a great idea to mix a small amount of compost into the bottom of the hole to provide a gentle nutrient boost.
Step 2: Position the Tuber
When you look at a dahlia tuber, you will notice a "neck" that connects the tuberous root to a piece of last year’s stem. This area is called the "crown," and it is where the "eyes" are located. The eyes are small bumps that will eventually become the new sprouts.
Lay the tuber horizontally in the hole with the eyes facing upward. If you cannot see the eyes yet, don’t worry; laying the tuber flat is a safe bet that allows the sprouts to find their way to the surface easily.
Step 3: Add Support Early
Most pom pom dahlias will eventually need support to keep their flower-heavy stems from leaning. It is best to drive a stake (like a wooden or bamboo pole) into the ground at the time of planting. By doing this now, you avoid accidentally poking through the tuber later in the season when the plant is larger.
Step 4: Cover with Soil
Fill the hole back in with soil, covering the tuber completely. You do not need to pack the soil down firmly; a light touch is better to keep the soil airy.
What to do next:
- Confirm your local last frost date before planting.
- Dig a 6-inch hole in a sunny, well-drained spot.
- Place the tuber horizontally with the "eye" pointing up.
- Install a sturdy stake next to the tuber now to save work later.
The Most Important Rule: Do Not Water Yet
One of the most common mistakes beginners make is watering their dahlias immediately after planting. Unlike many other plants, dahlia tubers do not have a root system yet. They are like a battery—they contain all the energy and moisture they need to send up that first sprout.
Adding water to the soil before the plant has roots to drink it up often leads to rot. In most cases, the natural moisture in the spring soil is more than enough. You should wait until you see the first green sprouts poking through the ground before you begin a regular watering schedule. This usually takes two to three weeks, depending on the temperature.
Caring for Your Growing Plants
Once your pom pom dahlias have emerged and are growing vigorously, their needs will change. Here is how to keep them thriving through the summer.
Watering Correctly
Once the plants are established, they appreciate deep, consistent watering. Instead of a light sprinkle every day, aim for a deep soak two or three times a week. This encourages the roots to grow deeper into the soil, making the plant more resilient during hot spells.
If you are growing your dahlias in containers, they will dry out much faster than those in the ground. Check the soil daily and water whenever the top inch feels dry.
Fertilizing for Blooms
Dahlias are "heavy feeders," meaning they use a lot of nutrients to produce their constant stream of flowers. We recommend using a fertilizer that is lower in nitrogen and higher in phosphorus and potassium (look for a 5-10-10 or 10-20-20 ratio).
High-nitrogen fertilizers can cause the plant to grow lots of lush green leaves but very few flowers. Start fertilizing once the plants are about a foot tall and continue every three to four weeks until mid-August. Always follow the instructions on the product label for the correct application amount.
The Power of Pinching
If you want a bushier plant with twice as many flowers, you must pinch and stake dahlias. This might feel a bit scary the first time you do it, but we promise it works wonders!
When your plant is about 12 inches tall and has four sets of leaves, use a clean pair of snips to cut off the very top of the center stem. This signals the plant to stop putting all its energy into one tall stalk and instead start growing multiple side branches. More branches mean more pom pom blooms for you to enjoy.
Managing Pests and Challenges
Gardening is a rewarding activity, and keeping a watchful eye on your plants makes it even easier. Pom pom dahlias are generally sturdy, but they do have a few fans in the insect world.
Slugs and snails are the most common visitors, especially when the plants are young and the leaves are tender. You can protect your sprouts by using a pet-safe slug bait or simply by checking your plants in the early morning and removing any intruders by hand.
As the weather gets humid in late summer, you might notice a white, flour-like dusting on the leaves. This is powdery mildew. You can minimize this by ensuring your plants have plenty of space for air to move through the leaves and by watering at the base of the plant rather than over the foliage.
Harvesting and Deadheading
The more you cut your pom pom dahlias, the more they will bloom. This makes them the perfect addition to a cutting garden.
How to Cut for Bouquets
Pom pom dahlias are excellent cut flowers because their stems are naturally stiff and straight. Unlike roses or lilies, dahlias do not open much after they are cut. Wait to harvest them until the flowers are at least three-quarters of the way open.
For the longest vase life, bring a bucket of water out to the garden with you and place the stems directly into it. Cutting in the cool of the early morning is also helpful, as the plants are most hydrated at that time.
Why Deadheading Matters
If you don't cut the flowers for bouquets, you should still remove the old blooms once they start to fade. This process is called "deadheading." When a plant produces seeds, it thinks its job for the year is done. By removing the fading flowers before they can make seeds, you trick the plant into thinking it needs to keep producing more blooms.
To deadhead, follow the flower stem down to where it meets a set of leaves and make a clean cut. Your garden will look tidier, and you will have flowers all the way until the first frost kills the foliage.
Key Takeaway: Pinching your plants at 12 inches and regular deadheading are the two best "easy wins" for a season full of flowers.
Season's End: What to Do in the Fall
In USDA hardiness zones 8 through 11, dahlia tubers can often stay in the ground year-round if the soil doesn't freeze. However, in most of the United States (zones 3 through 7), the tubers must be dug up and stored indoors if you want to grow them again next year.
After the first hard frost kills the foliage, the leaves will turn black or brown. This is your signal to act. Cut the stalks down to about four inches above the ground. If you have time, leave the tubers in the ground for a few days to "cure," which helps the skin toughen up for storage.
Carefully lift the tubers with a garden fork, being cautious not to nick the "necks" of the tubers, as this is where next year's growth will come from. Gently brush off the excess soil and let them air dry in a frost-free spot for a day or two.
Storing Your Tubers
Once dry, you can store your tubers in a cool, dark, and slightly humid place. A basement or an unheated garage that stays between 40°F and 50°F is ideal. Many gardeners find success placing the tubers in boxes filled with slightly damp peat moss, vermiculite, or wood shavings. This keeps them from drying out too much over the winter.
Check on your tubers once a month. If they look shriveled, give them a tiny mist of water. If any look soft or moldy, remove them immediately to keep the rest of the batch healthy.
Growing Pom Pom Dahlias in Containers
If you have limited garden space, you will be happy to know that pom pom dahlias grow beautifully in containers. This is a great way to bring color to a patio or balcony.
Choose the Right Container
Use a pot that is at least 12 inches deep and 12 inches wide. Larger is always better, as it provides more room for the tubers to grow and helps keep the soil moisture consistent. Ensure the pot has drainage holes in the bottom.
Use Quality Potting Mix
Fill your containers with a high-quality potting soil rather than garden soil. Garden soil is too heavy for pots and can become compacted, which prevents air and water from reaching the roots.
Container Maintenance
Plants in containers need more frequent watering and fertilizing than those in the ground. Because you are watering more often, the nutrients tend to wash out of the soil faster. Use a water-soluble fertilizer every two weeks to keep your container-grown dahlias blooming vigorously.
Summary of Success
Growing pom pom dahlias is a straightforward and enjoyable process when you follow a few basic steps. By matching the plant's needs to your garden's conditions, you can achieve professional-looking results with very little stress.
- Sun and Soil: Give them 6+ hours of sun and ensure the water drains away quickly.
- Patience at Planting: Wait for warm soil (60°F) and don't water until you see green sprouts.
- Support and Shape: Stake your plants at planting time and pinch the tops when they reach a foot tall.
- Consistent Care: Water deeply at the base and use a low-nitrogen fertilizer.
- Enjoy the Harvest: Cut blooms often to encourage the plant to keep producing.
At Longfield Gardens, we believe that every garden has room for the intricate beauty of pom pom dahlias. They are reliable performers that offer a massive return on a small investment of time.
"Pom pom dahlias prove that some of the most impressive things in the garden come in small, perfectly formed packages. Their geometric beauty is a highlight of the summer season."
We invite you to explore the dahlia collections available and start planning your most beautiful garden yet. If you have questions about your order, or need more specific advice for your region, our team is always here to help.
FAQ
How many flowers does a single pom pom dahlia plant produce?
A healthy, pinched pom pom dahlia plant can produce dozens of blooms over the course of a single season. Because the flowers are smaller than decorative or dinnerplate varieties, the plant has the energy to create a much higher volume of blossoms. You can expect a constant supply for bouquets from mid-July until the first frost.
Can I grow pom pom dahlias from seed?
While you can grow dahlias from seed, the resulting flowers will not be identical to the parent plant. Dahlias are genetically complex, and seeds usually produce a surprise mix of shapes and colors. To ensure you get the specific "pom pom" shape and a particular color, it is best to plant tubers, which are clones of the original variety.
Why are my dahlia flowers losing their petals or looking messy?
The most common reason for "messy" flowers is that they are past their prime. Dahlias bloom quickly, and individual flowers usually last about 4–6 days on the plant. Regular deadheading—removing the old flowers—will encourage the plant to produce fresh, tidy new blooms. Also, ensure you are watering at the base of the plant, as heavy water on the flower heads can cause them to droop or rot.
Do pom pom dahlias need special fertilizer?
They don't need a specific "dahlia" brand, but they do prefer a specific nutrient balance. Look for a fertilizer where the second and third numbers are higher than the first (such as 5-10-10). This ensures the plant focuses on building strong roots and many flowers rather than just growing tall, weak stems and green leaves. Avoid using high-nitrogen "lawn" fertilizers near your dahlias.