Growing different types of plants alongside dahlias can create a full and painterly display, enhancing the beauty of backyard borders and pots. However, some types of plants make better companions than others to these seasonal stars.
Firstly, it's important to choose neighbors with matching growing requirements, to ensure they all thrive. Of course, aesthetics is also something to bear in mind – you'll want to consider plants with complementary colors, contrasting textures, and variances in height. Some plants can also help tackle common pests, which makes growing dahlias slightly easier.
Below, you'll find top options to grow alongside your dahlias, recommended by gardening experts. Just be sure to give your plants enough space – even well-suited companions shouldn't be crowded. Remember to check if potential partners are seen as invasive in your region, too, as this can vary depending on where you are.
1. Purpletop vervain
Also known as Verbena bonariensis, this plant is a magnet for butterflies
'The airy elegance of purpletop vervain, or Verbena bonariensis, makes it an ideal companion for dahlias in mixed plantings,' says Peggy Anne Montgomery, a horticulturist at Garden Media Group.
'Its tall, wiry stems weave gracefully through dahlia foliage, adding soft purple-pink accents without overwhelming the scene. This subtle color pairs especially well with pink, purple, and white dahlias.
'Both plants are pollinator magnets, making them a winning choice for wildlife-friendly gardens,' she adds. 'Regular deadheading will encourage blooms to keep coming well into the season.' Both also require plenty of sunshine and well-draining soil to flourish.
Purpletop vervain seeds are available to buy from Burpee.
Peggy Anne Montgomery is a horticulturist with more than 35 years of experience in the industry in the Netherlands and the U.S. Her home garden has appeared on television, in several gardening books, and in many magazines. Today, she is an executive account manager at the Garden Media Group, where she represents Dutch Royal Anthos, the largest consortium of Dutch bulb growers and exporters in the U.S. and Canada.
2. Ornamental grasses
Ornamental grasses add movement and texture to the garden
Peggy Anne also recommends planting ornamental grasses alongside dahlias. They bloom later in summer, she says – 'perfectly overlapping with the dahlia season. Their feathery plumes and slender forms provide a beautiful contrast to the bold, rounded shapes of dahlia blooms. This mix of textures brings dynamic interest to any garden border.
'Many ornamental grasses also have reddish or bronze tones in their foliage and flower heads, making them a natural complement to warm-colored dahlias,' she adds. 'Both thrive in full sun and appreciate moist, well-drained soil.'
3. Holy basil
Holy basil produces spikes of small, white or purple flowers
Holy basil can be beneficial in tackling common dahlia pests. According to Deborah Stone of Stone Hollow Farmstead, it attracts pollinators as well as beneficial insects like hoverflies and predatory wasps, while its intense aroma deters pests such as aphids and white flies. 'It’s a beautiful, aromatic herb that also happens to be deeply functional,' she says.
Also known as tulsi, holy basil can be grown as a perennial in zones 10 to 11 and as an annual elsewhere. Deborah recommends letting it go to seed, and succession planting it every three to four weeks. 'This plant thrives in full sun with moderate watering.'
In 1999, after completing over 30 years of work within the aesthetic, cosmetic, and Medi-spa industries, Deborah Stone founded Stone Hollow Farmstead. The farm began with 80 raised beds of organic herbs and a small lab where Deborah produced her small batch skincare, Botaniko Skin, made from the herbs grown and distilled at the farm. Today, Stone Hollow produces award-winning culinary goods, herbal wellness products, and botanical skincare, and is renowned for its vibrant dahlia flowers.
4. Sweet alyssum
Try using this fragrant flower at the edges of your dahlia borders
'If you're looking for a plant that fills the space without overshadowing your dahlias, consider the sweet alyssum (Lobularia maritima),' says Nastya Vasylchyshyna, resident botany expert at Plantum. 'Known for its sweet honey scent, it draws pollinators, and its small white or pale pink flowers provide a lovely backdrop for your vibrant dahlias.
'The sweet alyssum thrives in neutral, well-drained, moist soil – similar to the conditions dahlias prefer. Growing low to the ground, it won’t compete for space, and while it loves full sun, it can tolerate some light shade.'
With its fast-growing, tiny flowers, it's also great for using as a 'spiller' around the edges of pots. Try 'Carpet Of Snow' seeds from Burpee for white blooms.
Nastya is a professional botany expert for the Plantum app that helps identify plants and plant diseases and provides care recommendations. Her specialization is plant morphology, phytopathology, and plant physiology.
5. Nasturtiums
Nasturtiums add pops of cheery color to the landscape
For an alternative ground cover that works well alongside dahlias, try nasturtiums (Tropaeolum), another suggestion from Nastya.
'These low-maintenance plants are highly adaptable and don’t require much fertilizer, so they won’t compete with dahlias for nutrients,' she says. 'They thrive in full sun, tolerate poor soil, and can handle moderate droughts, needing only weekly watering in open ground.
'Additionally, nasturtiums attract beneficial insects and pollinators, helping control pest populations,' Nastya adds. Like dahlias, they will flower well into the fall, adding dashes of fiery hues to your borders or container garden.
You can find a list of the best nasturtium varieties to grow in our dedicated guide.
FAQs
Is there another type of herb that works well alongside dahlias?
As well as holy basil, Deborah recommends planting dill alongside dahlias, highlighting how it attracts parasitic wasps and other beneficials that prey on aphids and mites.
Like dahlias, dill is a sun-lover. What's more, its umbels of small yellow flowers provide a pleasing contrast in form and texture to dahlias (both in the border and cut for bouquets). Dill tends to grow quite tall, however, so be careful to plant it somewhere where it won't block too much light from your dahlias.
What can you combine small varieties of dahlias with?
'For the front of borders, look to dwarf dahlias, which top out at around 18 to 20 inches,' says Peggy Anne. 'These compact charmers bloom in lively shades of red, orange, yellow, and pink and soft, creamy pastels.' She recommends pairing them with small, sun-loving annuals, such as cosmos and snapdragons.
Are shrubs good planting companions for dahlias?
It's generally best to avoid planting shrubs alongside dahlias, as they can outcompete them for nutrients and block out the sun. However, if you're looking for a structural backdrop behind your blooms, you could make an exception for eucalyptus.
'We interplant eucalyptus between every ten rows of dahlias to repel aphids, beetles, and possibly even spider mites,' says Deborah. 'Its fragrant foliage offers natural pest resistance and is a versatile addition to floral arrangements.
'It is an easy plant to care for: water regularly and provide a balanced fertilizer,' she adds. 'Eucalyptus thrives in hot climates, making it ideal for our Alabama fields.'
Bear in mind that eucalyptus can grow into huge trees, so look for compact varieties (such as Eucalyptus gunnii 'France Bleu') and ensure they aren't planted too close to your dahlias.
Learn how to keep dahlias blooming and you can enjoy these beauties for months on end. And, as well as admiring them outdoors, it's worth cutting some of the stems for vases in your home. If you need advice on how to arrange flowers, or even how to choose the right vase, our guides will help.
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