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With oversized personalities and star-studded blooms, dahlias are known to hog the garden spotlight, but they needn’t always be a solo act! You may be looking to grow dahilas in a mixed bed with other plants that will work well above or beneath them. You may want to pair them with something that will bloom in the early season, so your garden is never lacking in color. Or, you may even want to deter some of the pests that are known to plague dahlias or have done so in the past.
Whatever the reason you’re looking for some dahlia companionship, there are a few things to consider when making your selection. If you direct your attention to plants that will not crowd out or compete with dahlias but have the same exposure and watering requirements, you will be off to a good start. Some of the companions below will even plant well with dahlias in pots or containers.
Look for herbs that are known to detract or attract common dahlia insects, and work those in as a natural pest control. You may also want to consider some plants for the cutting garden that will complement your dahlias in a vase. Below are a few suggestions for meeting some of those requirements.
Nasturtium
Scientific Name: Tropaeolum majus
- Plant Type: Annual, herb
- Plant Size: 6 inch mound to 6 foot vine
- Sun Exposure: Full to part sun
- Hardiness Zone: 10-11
This colorful, fast growing favorite produces cheerful blooms in orange, red, white or yellow and leaves that are completely edible. Nasturtium are known to attract aphids, which are a major dahlia foe, so they are often planted nearby as a trap crop. But they also attract butterflies and bees, which is both lovely and helpful.
Like dahlias, nasturtium require well drained soil and a good amount of sun to thrive. Consider low mounding varieties in complementary colors as an understory plant or rambling vines as a backdrop.
Anise
Scientific Name: Pimpinella Anisum
- Plant Type: Annual, herb
- Plant Size: 18-24 inches tall and wide
- Sun Exposure: Full sun
- Hardiness Zone: 4-11
Often selected for its aphid deterrent reputation, anise sits just below most dahlia blooms and provides some delicate contrast. Early growth is rounded and feathery. Eventually, stalks of umbrella shaped florets with dainty white or slightly yellow blooms are sent up.
Anise need full sun and some wind protection to prevent breakage, so they make natural dahlia companions. Emitting an odor that both repels aphids and attracts predatory wasps, this one is a win-win.
Cilantro
Scientific Name: Coriandrum sativum
- Plant Type: Annual, herb
- Plant Size: 1-2 feet tall and wide
- Sun Exposure: Full to part sun
- Hardiness Zone: 2-11
Preferring 6 hours of morning light rather than harsh afternoon sun and crumbly, non-clay soil, cilantro shares most of dahlias’ growing conditions making it an ideal dahlia friend. With a scent that deters aphids and a dainty foliage profile, cilantro holds up nicely beneath a canopy of dahlias.
Artemisia
Scientific Name: Artemisia
- Plant Type: Perennial
- Plant Size: 3-5 feet tall, 2-3 feet wide
- Sun Exposure: Full
- Hardiness Zone: 3-8
This perennial’s soft, silvery foliage will not compete with your dahlias’ dramatic, oversized blooms. Artemisia is often selected as a companion plant because it does just the opposite. Its pale, cloud-like presence can be soothing when dahlias are doing their colorful thing. And it’s a natural slug repellent, which is always helpful.
Requiring full sun and good drainage, artemisia will fit right into your dahlia bed without changing your maintenance regimen, and the two can be cut at the same time to create an eye-catching floral arrangement.
Snapdragon
Scientific Name: Antirrhinum majus
- Plant Type: Annual or perennial
- Plant Size: 6-12 inches wide, 6 inches to 4 feet high
- Sun Exposure: Full sun to part shade
- Hardiness Zone: 7-11
With small, throated blooms of white, yellow, pink, red, orange, peach, purple and violet, snapdragon are prized in the dahlia garden for their early season bloom time. Standing in as colorful place holders for late season bloomers, snapdragon pack a punch through mid summer, when dahlias are just waking up.
Similar sun, soil and pH requirements and a vertical stature make this one a common addition to dahlia beds. Snapdragons can be grown as perennials, but are often grown as annual flowers, so keep that in mind if you plan on planting a flower garden that will re-bloom each season.
Geranium
Scientific Name: Pelargonium spp.
- Plant Type: Annual or perennial
- Plant Size: 6 inches to 4 feet tall and wide
- Sun Exposure: Full sun
- Hardiness Zone: 10-11
Full, flower heads on rigid spikes and dark rugged foliage give geranium their classic cottage charm and make them perfect pals for your dahlias. Round in habit and grown in full sun, geranium will fill in nicely beneath dahlia cultivars that are upright and more singular in nature.
Since Japanese beetles prefer them to dahlias, geranium can be planted nearby to draw these foes away from your prized blooms.
Sweet Alyssum
Scientific Name: Lobularia maritima
- Plant Type: Annual or perennial
- Plant Size: 3-9 inches tall, 6-12 inches wide
- Sun Exposure: Full to part sun
- Hardiness Zone: 5-9
A blanket of dainty white flowers come and go all season when sweet alyssum is worked into the landscape. When planted in pots, alyssum will mound and cascade over their sides, achieving both a filler and a spiller effect. Its small stature and fluffy profile contrasts nicely with dahlias’ strong, bold presence in any garden setting.
Sheer it back once a month or so and alyssum will continue to flower for as long as dahlias do. And it will act as a natural mulch of sorts, keeping tuberous roots cool and moist during hot spells.
Cosmos
Scientific Name: Cosmos bipinnatus
- Plant Type: Annual
- Plant Size: 1-3 feet tall, 1-3 feet wide
- Sun Exposure: Full sun
- Hardiness Zone: 2-11
With 4 inch blooms that keep coming from mid summer to fall, cosmos have unique spiky foliage and can be a nice underpinning plant for dahlias. Available in many colors and sizes, cosmos can be pinched to maintain a bushy habit or left alone to flourish in the middle garden. With growth requirements almost identical to dahlias, cosmos are a reliable and beautiful neighbor.
Coastal Lavender
Scientific Name: Limonium latifolium
- Plant Type: Perennial
- Plant Size: 6 inches to 3 feet tall, 2 feet wide
- Sun Exposure: Full Sun to part sun
- Hardiness Zone: 4-11
Early in the growing season, a rosette of leathery leaves will cover the ground beneath your dahlias, filling in some of the bare space. In mid-summer, just as your dahlias are about to show off, coastal lavender will send up sprays of purple, pink or white flowers to play a supportive role in the performance.
Coastal lavender is also a darling in the cutting garden, as it provides vertical structure and unusual leaf texture. Scatter this pretty perennial amongst the dahlias and you’ll always have a delightful mid-summer flower combo in your kitchen vase!
Daylily
Scientific Name: Hemerocallis spp.
- Plant Type: Perennial
- Plant Size: 8 inches to 5 feet tall, 2-4 feet wide
- Sun Exposure: Full Sun
- Hardiness Zone: 3-10
Easy to care for and tolerant of most growing conditions, daylilies come in a rainbow of vibrant colors and keep blooming through fall. Each flower only lasts for 24-36 hours but these old standbys are so prolific, you’ll never notice.
Their long, strappy leaves contrast nicely with dahlias’ darker, traditional form so the two pair well together in a mixed border. Just make sure you stay on top of them, because daylilies are considered invasive in some areas. Regular pruning and maintenance will be needed.
Joe Pye Weed
Scientific Name: Eutrochium
- Plant Type: Perennial
- Plant Size: 3-7 feet tall, 2-4 feet wide
- Sun Exposure: Full sun to part shade
- Hardiness Zone: 4-9
Although we typically think of dahlias as having a tall presence in the garden, and we usually try to imagine what can be planted under them, there are a couple of tall perennials that can be planted behind them to dramatic effect. This late blooming, upright wildflower grows in tall clumps, and its pretty mauve-pink flowers can soar to heights of at least 7 feet.
Joe pye weed’s sweet vanilla scent can make up for dahlias’ relatively odorless profile, and its blooms are a pollinator magnet. Like dahlias, it requires well drained soil, even watering, and plenty of sun. It might need staking to stay upright. Consider it a potential dahlia companion for larger beds and patches, since it takes up a lot of space.
Lady’s Mantle
Scientific Name: Alchemilla
- Plant Type: Perennial
- Plant Size: 12-18 inches tall and wide
- Sun Exposure: Full sun to part shade
- Hardiness Zone: 3-8
A clumping perennial with large, scallop shaped leaves and tiny yellow flowers, lady’s mantle is often placed in border fronts when showy flowers like dahlias are supposed to be the stars. Unassuming and subtle, but with its own unique personality, lady’s mantle has a grandma plant charm that pairs well with dahlias.
If not deadheaded regularly and divided annually, lady’s mantle will run through your bed and provide a groundcover effect. And that’s often what gardeners like about it.
Cranesbill
Scientific Name: Geranium
- Plant Type: Perennial, groundcover
- Plant Size: 20 inches tall to 24 inches wide
- Sun Exposure: Full sun to part shade
- Hardiness Zone: 4-10
Plentiful, cup-shaped blooms float to the top of a green leafy carpet when this perennial favorite is worked into your garden scape. Fast growing and spreading, cranesbill can have a mulch-like effect under your dahlias, keeping their feet cool and the soil moist.
In warmer regions, foliage is semi-evergreen and will hang around all winter, making it behave like a groundcover. With a bloom time that begins in spring and keeps going until late summer, cranesbill delivers a colorful punch while dahlias are still waking up.
Peonies
Scientific Name: Paeonia officinalis
- Plant Type: Perennial, shrub
- Plant Size: 3-4 feet tall and wide
- Sun Exposure: Full sun
- Hardiness Zone: 3-9
Charming and classic with a shrub-like habit and bountiful pink or white blooms, most peony varieties will pair naturally with dahlias in a cottage style garden. As early season bloomers, they’ll provide a pop of color during months when dahlias are not yet flowering. Later in the season, peonies’ large, dark foliage offers a nice contrast to dahlias’ kaleidoscope of color.
Plant them behind or in front of dahlias, depending on your cultivar, and be sure to allow plenty of space in between to keep air flowing and fungus at bay. Like dahlias, they might need stakes or cages to keep their heads up.
Fountain Grass
Scientific Name: Pennisetum
- Plant Type: Perennial, ornamental grass
- Plant Size: 1-4 feet tall
- Sun Exposure: Full sun
- Hardiness Zone: 3-10
For a change of pace and a stunning contrast, consider working some ornamental grass into your dahlia beds. Featuring long, strappy foliage in purple, burgundy or green, fountain grass also sends up long feathery blooms that last well into the fall. Its calm, breezy demeanor can be a nice offset to your dahlias’ big personalities and it also thrives in full sun.
Yarrow
Scientific Name: Achillea
- Plant Type: Perennial
- Plant Size: 2-3 feet tall and wide
- Sun Exposure: Full sun
- Hardiness Zone: 3-9
Defined by fern-like foliage and flat-topped yellow, white, or pink flowers, achillea is at home both above and beneath a canopy of dahlias. Its stalks are roughly 4 times its foliage height, so depending on which dahlia cultivar you’re working with, they can intermingle or stand out.
Yarrow’s unique flower shape pairs nicely with large, round dahlia blooms and makes an excellent addition to the cutting garden. With similar bloom time and growth requirements, yarrow and dahlia are a winning combination.
Yarrow is also a great warm weather plant, and it can be planted as late as July if you need something to liven up your summer garden space..
Tulips
Scientific Name: Tulippia spp.
- Plant Type: Perennial, bulb
- Plant Size: 6-24 inches
- Sun Exposure: Full sun
- Hardiness Zone: 4-10
If you’re looking for something to fill in and shine before dahlias have their turn, tulips are a great choice. Available in a broad array of sizes and colors and easy to grow, tulips will flower in spring and early summer then fade when dahlias are beginning to burst.
Foliage can be braided or turned under and ‘hidden’ as dahlias fill out. Since we don’t want to cut bulb stalks down until they’re completely brown, the two flowers have a symbiotic relationship. This means dahlias and tulips make wonderful bedfellows.
Final Thoughts
When choosing companion plants for your dahlias, start with sun lovers that thrive in well-drained soil. From there, consider your height and space needs, being careful to choose plants that allow dahlias ample air flow and root space.
Throw in flowering time, cutting garden characteristics, and pest control needs, and you’ll have narrowed the field down considerably. With a little trial and error, your dahlias will have made some new friends and your garden will be constantly buzzing with beautiful blooms.
