Dahlias (Dahlia pinnata), perennial flowers native to Mexico, are known for their ability to bloom vividly in warm, sunny climates. With their wide array of colors, shapes, and sizes, these flowers can undoubtedly make a spectacular display on their own. However, their beauty truly enhances when accompanied by certain companion plants.
But with the countless choices of flowers, herbs, and vegetables, choosing a suitable companion for dahlias can be overwhelming. That’s why we’ve put together a comprehensive list of plants that make excellent companions, and those you should avoid when growing dahlias.
Understanding Companion Planting
Companion planting is an age-old practice of growing two or more different plant species together with the intention of benefitting each other, thereby promoting overall growth and health organically. Originating from Native American tribes nearly 10,000 years ago, this technique is now popularly practiced worldwide, with both crop plants and ornamental plants.
A classic example of companion planting is the “Three Sisters” method—growing beans, sweetcorn, and squash together. Each of these crop plants supports the other in some way, ultimately benefitting the grower. Beans, a nitrogen-fixing legume, provide nutrients for sweetcorn and squash. Sweetcorn serves as a sturdy support for beans to climb upon, and squash plants, growing low to the ground, help retain soil moisture and suppress weed growth.
Benefits of Companion Planting
Companion planting provides numerous benefits, from pest control to aesthetics. Many plants naturally deter garden pests through strong scents or chemicals, negating the need for chemical pesticides. Others attract predator insects that control pest populations—a biological pest control strategy.
Companion planting also boosts soil health. Legumes like beans, peas, and lentils, known as nitrogen fixers, improve soil quality by converting atmospheric nitrogen into a plant-usable form. Deep-rooted plants help break up the soil, enhancing its drainage and preventing waterlogging.
For ornamental species like dahlias, companion planting enhances aesthetics. By mixing annuals and perennials, you can enjoy a prolonged blooming period. Complementary or contrasting displays can be created for visual appeal. Additionally, companion planting attracts a diverse range of pollinators, reduces nutrient competition, and varies root water and nutrient uptake depths.
Selecting Dahlias’ Companion Plants: Considerations
When deciding on dahlias’ companion plants, several factors need consideration. For instance, the chosen plants must thrive under similar growing conditions. The soil type, aesthetic appeal, plant seasonality, and individual plant characteristics should align for optimal growth and compatibility.
Ideal Companion Plants for Dahlias
To enjoy a stunning dahlia display, choose companions that thrive in warm, sunny, sheltered spots with fertile, well-draining, neutral to slightly acidic soil. Dahlia companions can be flowers or herbs that either bloom early, repel insect pests, or add contrasting textures. Some of the best companions for dahlias include:
- Aster: Like dahlias, asters attract pollinators and contribute to a vibrant summer display.
- Thyme: This herb’s strong scent repels pests and adds texture to dahlias.
- Marigolds: Their unique scent deters pests and their vibrant colors contrast beautifully with dahlias.
- Sweet Alyssum: Ideal for ground cover, sweet Alyssum keeps the soil moist and cool.
- Fountain Grass: This ornamental grass adds contrasting texture and interest.
- Bee Balm: Its strong scent attracts pollinators, and its leaves provide shade, helping retain soil moisture.
- Cosmos: These hardy annuals tolerate various soil conditions and complement dahlias without competing for resources.
Plants to Avoid When Growing Dahlias
While many plants complement dahlias, some should be avoided, including fruit and vegetable plants (due to pest attraction), grasses (potential nutrient competition), heavy feeders (risk of nutrient competition), and climbing plants (can damage fragile dahlia stems).
In conclusion, choosing the right companions for your dahlias can greatly enhance your garden’s visual appeal and overall health. By considering the conditions, aesthetics, and individual characteristics of potential companion plants, you can create a stunning and vibrant dahlia display.