Introduction
There is a special kind of magic that happens in the garden when the first dahlia buds begin to unfurl. These plants are the undisputed stars of the late summer border, offering a spectacular range of colors and sizes that few other flowers can match. At Longfield Gardens, we know that while a field of dahlias is breathtaking, these versatile flowers also shine when paired with the right neighbors.
Whether you want to hide the "legs" of tall varieties, fill in gaps while you wait for mid-summer blooms, or naturally manage garden pests, choosing the right companion plants makes your gardening experience even more rewarding. This guide will help you select the best partners for your dahlias to create a lush, healthy, and vibrant landscape. By understanding the needs of your tubers and matching them with compatible plants, you can enjoy a garden that looks professional and thrives all season long.
Understanding the Needs of Your Dahlias
Before choosing companions, it is helpful to look at what makes a dahlia thrive. These plants are sun-seekers that love warm soil and plenty of food. They are often called "heavy feeders," which simply means they need a good supply of nutrients from the soil to produce those massive, colorful blooms.
When you look for plants to grow alongside them, the most important rule is to choose neighbors that share the same lifestyle. Most dahlias need at least six to eight hours of direct sunlight every day. If you plant them next to a tall, sprawling shrub that casts deep shade, your dahlias will likely grow tall and spindly as they reach for the light.
Drainage is another key factor. Drainage is how fast water leaves the soil. Dahlias prefer soil that stays moist but never soggy. Planting them with moisture-loving bog plants or extremely drought-tolerant cacti usually leads to one plant being unhappy. Instead, look for companions that enjoy regular watering and well-drained, fertile soil.
Finally, consider the space. Dahlias need good air circulation to stay healthy and avoid common issues like powdery mildew. Avoid packing companions so tightly that air cannot move through the leaves. Giving each plant a little "breathing room" is one of the easiest ways to ensure a successful season.
Key Takeaway: Match your dahlias with plants that also love full sun and well-drained soil. This simple step ensures every plant in the bed has exactly what it needs to flourish.
Early Season Fillers
Dahlias are not exactly early birds. We typically wait to plant the tubers until the soil is warm—about 60°F—and the danger of frost has passed. Because they take a few months to reach their full glory, the garden bed can look a bit bare in May and June. This is where early season companions come in to save the day.
Snapdragons
Snapdragons are wonderful "placeholders" in the dahlia garden. They love the cooler weather of late spring and early summer. By the time your dahlias are starting to gain height, the snapdragons are already in full bloom. As the heat of mid-summer arrives and the snapdragons begin to fade, your dahlias will be ready to take over the spotlight.
Sweet Alyssum
If you want a plant that works hard from day one, sweet alyssum is an excellent choice. This low-growing annual creates a carpet of tiny, honey-scented white or purple flowers. It is perfect for filling in the front of the border or the spaces between dahlia stakes. Because it grows as a thick mat, it acts like a "living mulch," helping to keep the soil cool and suppressing weeds.
California Poppies
These cheerful, bright orange or yellow flowers are very easy to grow from seed. They are relatively thin and spindly, meaning they won't compete with your dahlias for space or nutrients. They provide a splash of color in early summer and often self-seed, returning to greet you again the following year.
Steps for Early Season Success
- Plant sweet alyssum seeds around the edges of your dahlia beds as soon as the soil can be worked.
- Use snapdragons to provide vertical color while dahlia sprouts are still small.
- Leave enough space between the early bloomers to plant your dahlia tubers without disturbing roots.
Beautiful Foliage Partners
Sometimes the best companion for a bright flower isn't another flower, but interesting foliage. Dahlias have lush, green (and sometimes dark burgundy) leaves, but adding different textures and colors to the mix can make the blooms pop even more.
Dusty Miller
Dusty miller is a favorite for many home gardeners because of its silvery-white, lacy leaves. The silver color provides a stunning contrast to the deep reds, pinks, and purples of dahlia varieties like 'Thomas Edison' or 'Cornel'. It stays relatively short, making it a great choice for hiding the lower stems of taller dahlia plants.
Artemisia
Similar to dusty miller, Artemisia offers beautiful silver foliage. Varieties like 'Silver Mound' create a soft, pillowy texture at the base of your dahlias. An added benefit is that the scent of Artemisia is often a deterrent for slugs and snails, which are known to enjoy snacking on young dahlia shoots.
Ornamental Grasses
Grasses like Pennisetum (fountain grass) or smaller varieties of Miscanthus add a sense of movement to the garden. The fine texture of the grass blades contrasts beautifully with the broad leaves of the dahlia. As autumn approaches, the seed heads of the grasses and the late-season dahlia blooms create a sophisticated, textured look that lasts until the first frost.
Natural Pest Management and Pollinators
In any healthy garden, we want to invite the "good bugs" in to help manage the "bad bugs." Some companion plants are specifically chosen because they act as guardians for your dahlias.
Salvia
Salvias are powerhouses for attracting pollinators. Hummingbirds, bees, and butterflies love the upright spikes of nectar-rich flowers. By inviting these visitors to your garden, you are also inviting predatory insects that help keep aphid populations under control. The tall, spiky form of salvia looks fantastic when planted behind or alongside the rounded shapes of "Pompon" or "Ball" dahlias.
Nasturtiums
Nasturtiums are often used as a "trap crop." This means they are actually more attractive to certain pests, like aphids, than the dahlias are. By planting nasturtiums a short distance away, you can lure the aphids away from your prize blooms. Beyond their utility, nasturtiums offer beautiful trailing foliage and edible flowers in warm tones that complement "Dinnerplate" dahlias like 'Cafe au Lait'.
Yarrow (Achillea)
Yarrow is a hardy perennial that produces flat-topped flower clusters. These clusters are landing pads for ladybugs and lacewings, both of which are natural enemies of common garden pests. Yarrow is also very drought-tolerant once established, making it a low-maintenance partner that won't mind if the dahlias take a bit more of the water and fertilizer.
Key Takeaway: Using "guardian" plants like Salvia and Nasturtium helps create a balanced ecosystem in your garden, reducing the need for extra interventions.
Height and Structure Companions
Because dahlias can range from two feet to over five feet tall, you can use companion plants to create layers of color. This makes the garden feel full and intentional.
Verbena bonariensis
This plant is a favorite of professional garden designers. It produces tall, wiry stems topped with clusters of tiny purple flowers. Because the stems are so thin, you can see right through them. This "see-through" quality allows you to plant it in front of or amongst your dahlias without hiding them. It adds a misty purple haze to the garden that looks incredible in the late afternoon sun.
Cosmos
Cosmos and dahlias are a classic pair. They both love the sun, they both bloom for a long time, and they both make excellent cut flowers. Cosmos have feathery, fern-like foliage that adds a light, airy feeling to the bed. Since they can grow quite tall, they are perfect for filling in the gaps between larger dahlia varieties.
Nicotiana (Flowering Tobacco)
Dahlias are famous for their looks, but most varieties do not have a strong scent. If you want your garden to smell as good as it looks, try planting Nicotiana. These plants produce starry flowers that release a sweet fragrance, especially in the evening. They come in various heights, so you can find a variety that tucks perfectly into your dahlia border.
Herbs as Companions
Many common kitchen herbs make wonderful neighbors for dahlias. They are often fragrant, attractive, and helpful for deterring pests.
- Lavender: The silvery foliage and purple spikes of lavender look beautiful at the feet of taller dahlias. Lavender enjoys the same sunny spots and can help deter some unwanted insects with its strong scent.
- Anise: This herb produces delicate, umbrella-shaped white flowers. It is known to attract predatory wasps that hunt aphids, making it a functional and pretty addition to the bed.
- Cilantro: If you let your cilantro "bolt" (go to flower), it produces airy white blooms that look like lace. These flowers are a magnet for beneficial insects.
Designing With Color and Shape
When you are deciding what can you plant with dahlias, think about the visual "vibe" you want to create. You can choose companions based on color harmony or color contrast.
The "Hot" Border
If you love vibrant oranges, reds, and yellows, pair your dahlias with plants like Canna lilies, zinnias, or orange cosmos. This creates a high-energy look that feels like a sunset in your backyard.
The Pastel Garden
For a softer look, choose dahlias in shades of peach, cream, and lavender (like the famous 'Cafe au Lait'). Pair these with silver foliage plants like Dusty Miller, or light purple flowers like Verbena and light pink snapdragons. This creates a romantic, cottage-garden feel.
Playing with Shapes
Dahlias come in many forms—stars, balls, waterlilies, and huge dinnerplate dahlias. Use companions with different shapes to create interest.
- Spikes: Use Salvia or Snapdragons to contrast with round dahlias.
- Daisies: Use Cosmos or Zinnias for a simple, classic flower shape.
- Lace: Use Yarrow or Anise for a fine-textured look.
Planting Tips for Success
At Longfield Gardens, we want your garden to be a place of relaxation, not a source of stress. Getting the planting process right is the best way to ensure your companions and dahlias get along.
Give Them Space
It is tempting to pack plants close together for an instant full look. However, dahlias grow significantly larger than they appear when you first plant the tubers. A small 'Thomas Edison' tuber will eventually become a three-foot-wide bush. Always check the expected width of your dahlia variety and leave enough room for its companions to breathe.
Fertilizing and Watering
Because dahlias are heavy feeders, they may hog the nutrients in the soil. When planting companions nearby, you may need to provide a little extra compost or a balanced fertilizer to ensure everyone gets enough to eat. When watering, try to water at the base of the plants. This keeps the leaves dry, which is the best way to prevent spots and mildews.
Support Your Dahlias
Many dahlias need stakes to keep their heavy blooms from flopping over. If you plan to use stakes, put them in the ground at the same time you plant your tubers. This prevents you from accidentally driving a stake through a companion plant's roots later in the season.
What to do next:
- Map out your dahlia bed, marking where the tall, medium, and short varieties will go.
- Choose at least one foliage plant and one pollinator plant as companions.
- Install your dahlia stakes early to avoid disturbing neighboring plants later.
Realistic Expectations for Your Garden
Gardening is a partnership with nature, and nature sometimes has its own plans. While these companion plants are generally excellent matches, your specific results will depend on your local weather, soil type, and microclimate.
For example, in a very rainy year, your sweet alyssum might grow faster than usual, or in a very hot year, your snapdragons might stop blooming earlier than expected. This is all part of the fun! If a combination doesn't work perfectly the first time, don't be discouraged. Part of being a gardener is observing how plants interact and making small adjustments each year.
The timing of your blooms will also vary. We ship our tubers from our facility in Lakewood, New Jersey, according to your USDA hardiness zone so they arrive at the right time for planting. However, a late spring chill or an early heatwave can shift your blooming schedule by a week or two. Treat your garden as an evolving work of art rather than a rigid plan.
Conclusion
Creating a beautiful garden is about more than just picking a single favorite flower; it is about building a community of plants that support and enhance one another. By pairing your dahlias with early-season fillers, protective herbs, and textured foliage, you create a landscape that is resilient and stunning from spring through fall. We at Longfield Gardens are proud to provide the high-quality tubers and perennials you need to make these combinations a reality.
- Focus on the basics: Ensure all companions share the dahlia's love for sun and well-drained soil.
- Add layers: Use different heights to hide "bare legs" and create a full, lush look.
- Think ahead: Use early bloomers like snapdragons to keep the garden colorful while dahlias grow.
- Invite helpers: Plant salvias and yarrow to attract the beneficial insects that protect your garden.
The most successful gardens are those where the plants work together. When you choose the right companions for your dahlias, you aren't just planting a bed; you're growing a thriving ecosystem.
The next step is simple: pick a color palette you love, select a few of our premium dahlia varieties, and choose two or three companions to join them. You’ll be rewarded with a garden that brings joy to you and the pollinators all season long.
FAQ
Can I plant dahlias with vegetables?
Yes, you can certainly plant dahlias in or near a vegetable garden. They share similar needs with many summer vegetables, such as tomatoes and peppers, which both love full sun and regular nutrients. Some gardeners plant dahlias at the ends of vegetable rows to attract pollinators that will then help pollinate crops like squash and beans.
Will companion plants take too many nutrients away from my dahlias?
Dahlias are hungry plants, but they can coexist happily with companions as long as you provide enough food for everyone. Adding a layer of compost at the start of the season and using a balanced fertilizer throughout the summer ensures that your dahlias and their neighbors stay healthy and vibrant without competing.
What is the best plant to hide the bottom of dahlia stems?
Lower-growing plants like sweet alyssum, dusty miller, or mounding varieties of nasturtium are excellent for this. They create a "skirt" of foliage and flowers that covers the woody lower stems of taller dahlias, giving the entire garden bed a more finished and cohesive look.
Do I need to worry about companion plants attracting pests?
While some plants like nasturtiums are used specifically to attract aphids away from dahlias, most companions like salvia and yarrow actually help reduce pest problems by inviting beneficial insects. The key is to create diversity in the garden, which naturally helps keep any single pest population from becoming a major issue.
