Can You Plant Dahlias with Roses?

Table of Contents

1. Introduction
2. The Benefits of Pairing Dahlias and Roses
3. Getting the Environment Right
4. Choosing the Right Varieties
5. The Fertilizer Balance
6. Planting Step-by-Step
7. Maintaining the Mixed Border
8. Managing the Seasons
9. Troubleshooting Common Issues
10. Creative Design Ideas
11. Conclusion
12. FAQ

Introduction

There is a specific kind of magic that happens in a late-summer garden when the soft, romantic blooms of roses meet the bold, architectural presence of dahlias. If you have ever stood in your garden wishing for more color during those weeks when roses take a mid-season breather, you are not alone. Combining these two garden heavyweights is a fantastic way to ensure your landscape remains vibrant from early summer straight through the first frost.

At Longfield Gardens, we believe that every gardener can achieve a professional-looking display by understanding how different plants work together. Many people wonder if the "Queen of Flowers" can share her throne with the "Diva of the Autumn Garden." The answer is a resounding yes. While they have slightly different growth habits, their needs for sun and soil are remarkably similar, making them natural partners in a well-planned border.

This guide will explain how to successfully grow dahlias and roses side-by-side. We will cover everything from choosing the right varieties to managing their unique feeding requirements. By following a few simple steps, you can create a high-impact garden bed that offers a non-stop show of color and fragrance.

The Benefits of Pairing Dahlias and Roses

Planting dahlias and roses together is more than just a stylistic choice; it is a smart strategy for a continuous harvest of flowers. Roses often have their most dramatic flush in late spring and early summer. While many modern shrub roses are "remontant" (meaning they bloom again), there is often a quiet period in July and August when the heat slows them down.

This is exactly when dahlias begin to hit their stride. Dahlias love the warmth of summer and will continue to produce more flowers the more you cut them. By the time your roses are preparing for their secondary fall flush, your dahlias will be at their peak. This overlap creates a seamless transition of color that keeps your garden looking lush even as the season shifts.

Beyond timing, the visual contrast is stunning. Roses often have rounded, cupped, or ruffled petals with a soft, matte texture. Dahlias, on the other hand, offer an incredible range of shapes, from the perfectly geometric "ball" types to the wild, spiky "cactus" varieties. Placing a sleek, dinnerplate dahlia like 'Cafe au Lait' next to a creamy white shrub rose adds a layer of sophistication and depth that a single-species garden can’t quite match.

Getting the Environment Right

Both roses and dahlias are sun-lovers, which is the primary reason they work so well in the same bed. Before you start digging, you need to ensure the location meets the basic requirements for both plants to thrive.

Sunlight Needs

To get plenty of blooms, your garden bed needs at least six to eight hours of direct sunlight every day. If the spot is too shady, your roses may become "leggy" as they reach for the light, and your dahlias may produce weak stems that flop over. Full sun also helps the foliage dry quickly after rain or dew, which is the best way to keep both plants healthy and vibrant.

Soil and Drainage

"Drainage" simply refers to how fast water leaves the soil. Neither roses nor dahlias like to sit in "wet feet," which can lead to root or tuber rot. If your soil is heavy clay, we recommend adding some compost or aged manure to help loosen it up. Ideally, the soil should be crumbly and rich in organic matter. This allows the rose roots to grow deep and the dahlia tubers to expand easily throughout the season.

Airflow and Spacing

Good airflow is a quiet winner in the garden. Both roses and dahlias can be susceptible to powdery mildew if they are packed too tightly together. When planning your bed, give each plant enough room to breathe.

• Roses: Depending on the variety, most shrub roses need about 3 feet of space.
• Dahlias: Mid-to-tall varieties usually need 18 to 24 inches between plants.

When planting them together, make sure the dahlias aren't placed so close that they completely shade the lower leaves of the rose bushes. A little breathing room goes a long way toward keeping the foliage looking green and fresh.

Key Takeaway: Success starts with the right location. Choose a spot with 6+ hours of sun and soil that doesn't stay soggy after a rainstorm.

Choosing the Right Varieties

The secret to a beautiful mixed bed is "layering." You want to consider the height and width of both the roses and the dahlias so they don't hide each other. At Longfield Gardens, we offer a wide range of dahlias that fit different roles in the garden, from tall back-of-the-border beauties to compact varieties for the front edge.

Using Height to Your Advantage

If you have tall climbing roses on a fence or trellis, you can plant tall "Dinnerplate" or "Decorative" dahlias in front of them. Varieties like 'Thomas A. Edison' (a deep purple) or 'Labyrinth' (a mix of peach and pink) can reach 3 to 4 feet tall. They provide a lush mid-ground layer that hides the often "woody" base of older rose bushes.

For shorter shrub roses or "Floribunda" types, consider using "Border" or "Melody" dahlias. These typically stay under 2 feet tall. They act as a colorful skirt around the roses, filling in gaps without competing for the same vertical space.

Color Coordination

You can either go for a harmonious look or a high-contrast look.

• Harmonious: Pair soft pink roses with white and blush dahlias like 'Cafe au Lait'. This creates a romantic, cottage-garden feel.
• Contrast: Pair yellow or white roses with bold, dark dahlias like Arabian Night or Rip City. The dark foliage of some dahlia varieties also makes the bright colors of rose petals "pop."

The Fertilizer Balance

This is the most important technical detail when growing these two together. Roses are heavy feeders and they love nitrogen, which helps them grow strong canes and lots of leaves. However, if dahlias get too much nitrogen, they tend to grow massive amounts of green foliage but very few flowers. In some cases, high nitrogen can even cause dahlia tubers to rot or fail to develop properly for the following year.

How to Feed a Mixed Bed

The best approach is to be intentional about where you put your fertilizer.

1. Feed the soil first: When you first prepare the bed in spring, mix in a good amount of compost. This provides a gentle, slow-release source of nutrients that benefits both plants.
2. Target the roses: When it is time to give your roses their specific rose food, apply it directly to the base of the rose bush and lightly scratch it into the soil. Avoid broadcasting or "scattering" the fertilizer over the entire bed.
3. Low-nitrogen for dahlias: For the dahlias, use a fertilizer that is higher in phosphorus and potassium (the second and third numbers on the bag) rather than nitrogen (the first number). This encourages bloom production rather than just leaf growth.

Action Plan for Feeding:

• Apply compost to the whole bed in early spring.
• Give roses a balanced rose fertilizer in May and July, applied only to their root zone.
• Give dahlias a "bloom booster" style fertilizer once a month starting in July.
• Stop all fertilizing by late August to let the plants prepare for the end of the season.

Planting Step-by-Step

Timing is everything when it comes to planting dahlias. While roses are often planted in early spring while they are still dormant, dahlia tubers are tropical and cannot handle frost.

1. Planting the Roses

If you are starting a new bed, plant your roses first. This is usually done in early spring as soon as the soil can be worked. Dig a hole twice as wide as the root ball and just as deep. Ensure the "graft union" (the bump where the rose is joined to the roots) is at the correct level for your zone—usually at or just below the soil surface in cooler climates.

2. Waiting for Warm Soil

Wait to plant your dahlia tubers until the soil has warmed up to at least 60°F and all danger of frost has passed. In most parts of the US, this is around the same time you would plant tomatoes or zinnias. For more timing guidance, see When Should I Plant Dahlia Tubers?.

3. Placing the Tubers

Dig a hole about 4 to 6 inches deep. Lay the tuber horizontally with the "eye" (the small bump where the sprout will come from) pointing up. If you are planting tall varieties, this is the best time to put a stake in the ground. Staking at planting time ensures you don't accidentally poke a hole through the tuber later in the summer. For more detail, see How Deep Should I Plant Dahlia Tubers?.

4. Initial Watering

Water your roses well after planting. However, hold off on heavy watering for the dahlias until you see the first green sprouts poking through the soil. The tubers have enough moisture stored inside to get started, and too much water in cold, early-spring soil can cause them to struggle.

Maintaining the Mixed Border

Once your garden is established, the maintenance is quite straightforward. Because both plants are prolific bloomers, your main job will be "deadheading."

Deadheading for More Blooms

Deadheading is simply the act of removing faded flowers. For roses, cut back to the first set of five leaves to encourage a strong new stem. For dahlias, follow the stem down to where it meets a main branch and make your cut there. This prevents the plants from putting energy into making seeds and keeps them focused on producing more flowers. For more on basic care, see All About Dahlias.

Deep Watering

Both roses and dahlias prefer deep, infrequent watering over a light daily sprinkle. Aim to provide about an inch of water per week, either through rain or your garden hose. Use a soaker hose or aim your watering can at the base of the plants. Keeping the water off the leaves is the best way to prevent common issues like black spot on roses or mildew on dahlias.

Mulching

A two-inch layer of organic mulch, such as shredded bark or pine needles, is a gardener’s best friend. It helps the soil retain moisture, keeps the roots cool during the heat of July, and prevents weeds from moving in. Just be sure to keep the mulch a few inches away from the main stems of the roses and the dahlia sprouts to allow for good air circulation.

Managing the Seasons

One of the main differences between these two plants is how they handle winter. Roses are hardy perennials that stay in the ground all year. In most of the US (Zones 3-7), dahlias are treated as annuals or "tender perennials," meaning the tubers must be dug up and stored indoors if you want to grow them again next year. To check your zone, see our Hardiness Zone Map.

The Fall Transition

When the first frost hits, your dahlias will turn black and go dormant. This is your signal to act.

1. Cut back the dahlias: Cut the dahlia stems down to about 4 inches above the ground.
2. Wait a week: Let the tubers "cure" in the ground for about a week to help toughen the skins.
3. Lift carefully: Use a garden fork to gently lift the dahlia tubers. Be careful not to nick them.
4. Rose care: While you are lifting the dahlias, your roses stay right where they are. This is a good time to clear away any fallen rose leaves to prevent diseases from over-wintering in the soil.

By removing the dahlias each fall, you actually create a great opportunity to add some compost to the empty spots, which will benefit the roses next spring.

Key Takeaway: You get the best of both worlds by leaving the roses in place and lifting the dahlias for winter storage. It keeps the bed healthy and ready for a fresh start each spring.

Troubleshooting Common Issues

Even the most experienced gardeners run into a few hiccups. The key is to keep things simple and address issues as soon as you see them.

Why Aren't My Dahlias Blooming?

If your dahlias are all leaves and no flowers, it is usually due to one of three things:

• Too much nitrogen: Check your fertilizer. Switch to a bloom-booster formula.
• Not enough sun: If the roses have grown so large they are shading the dahlias, you may need to move the dahlias to a sunnier spot next year.
• Lack of deadheading: If the plant starts making seed pods (which look like pointed green cones), it will stop making new flowers. Keep cutting!

Dealing with Pests

Aphids and Japanese beetles sometimes enjoy both roses and dahlias. In most cases, a strong blast of water from the garden hose is enough to knock aphids off the plants. For beetles, the most effective method is simply picking them off in the morning and dropping them into a bucket of soapy water. Keeping the garden clean and well-spaced is your best defense against most pests.

Creative Design Ideas

If you are looking for inspiration on how to layout your mixed bed, here are three simple "recipes" for success using plants we carry:

The Romantic Cottage Garden

• The Rose: A soft pink climbing rose on a trellis.
• The Dahlia: 'Cafe au Lait' (Dinnerplate) and 'Boom Boom White' (Ball).
• The Look: Dreamy, soft textures that look incredible in a vase.

The High-Energy Border

• The Rose: A bright yellow or white Floribunda shrub rose.
• The Dahlia: 'Thomas A. Edison' (Purple) or 'Akita' (Red and Yellow).
• The Look: High-contrast colors that catch the eye from across the yard.

The Sunset Bed

• The Rose: Apricot or coral-toned shrub roses.
• The Dahlia: Labyrinth (Peach/Pink) or Maarn (Orange Ball).
• The Look: Warm, glowing tones that look best in the late afternoon sun.

Conclusion

Planting dahlias with roses is a wonderful way to elevate your garden and extend your blooming season. By matching their shared love for the sun and managing their feeding needs individually, you can create a high-impact display that brings joy from June until October. At Longfield Gardens, our goal is to help you find the perfect combinations that make gardening feel like a rewarding adventure rather than a chore, and our 100% Quality Guarantee helps make that easier.

Remember these simple steps for a successful mixed bed:

• Ensure at least 6 hours of daily sunlight.
• Give each plant room to breathe to prevent mildew.
• Feed roses directly at the base and keep dahlias on a low-nitrogen diet.
• Deadhead regularly to keep the flowers coming all summer long.

"The combination of the rose's classic elegance and the dahlia's bold variety creates a garden that feels both timeless and excitingly modern."

We invite you to explore our selection of premium dahlia tubers and start planning your most beautiful garden yet. If you want to review how shipping works before you order, see our Shipping Information. With a little bit of planning and the right plants, your yard will be the highlight of the neighborhood.

FAQ

Will dahlias crowd out my roses?

Dahlias grow very quickly in the summer and can become quite large. To prevent them from crowding your roses, leave at least 24 inches of space between the rose bush and the dahlia tuber. If a dahlia starts to lean too far over a rose, simply stake the dahlia or prune back a few of its side branches to restore airflow.

Can I use the same fertilizer for both?

While you can use a general-purpose balanced fertilizer, it is better to be specific. Roses love nitrogen for growth, but too much nitrogen can stop dahlias from blooming. We recommend applying rose-specific food to the roses and a low-nitrogen, high-phosphorus "bloom booster" to the dahlias for the best results from both.

Do I have to dig up the dahlias if they are next to roses?

In USDA zones 7 and colder, dahlia tubers will freeze and rot if left in the ground over winter. You should dig them up after the first frost. This actually works well for the roses, as it gives you a chance to clean up the garden bed and add fresh compost around the rose roots without disturbing the dahlias.

When is the best time to plant them together?

Roses are best planted in early spring while the weather is still cool. Dahlias, however, are very sensitive to cold and should only be planted once the soil is warm (60°F) and the danger of frost has passed. This usually means planting your roses first and then "tucking" the dahlias into the gaps a few weeks later.