Every year, Martha and I cultivate a diverse range of dahlia varieties on our farm. We appreciate dahlias for their vibrant summer and fall blooms, which inject much-needed color into the garden during the hotter months when other flowers have faded. Additionally, their wide range of colors, sizes, and shapes makes dahlias particularly appealing.
On our farm, we plant three to five plants of each dahlia variety annually. We maintain a stock of dahlia tubers, adding new varieties each season. My personal favorites are the giant dinner plate dahlias, known for their impressive blooms that can fill an entire vase.
If you’re interested in growing dahlias, here are some tips for planting and caring for these beautiful flowers to enhance your garden at home.
Choosing Dahlia Varieties
Dahlias offer flexibility in garden design. They can be grown in large mixed beds or in rows dedicated solely to cutting. You can also plant them in small groups within landscape gardens or scattered throughout.
Select dahlia varieties based on how you want to display them. For example, use shorter varieties for bed edges, medium-sized ones throughout your landscape, and tall varieties for height and structure at the back of beds. Consider the foliage as well—some dahlias feature dark, nearly black leaves, which can add extra visual interest.
Selecting the Right Planting Location
Dahlias thrive in sunny spots, requiring at least eight hours of full sun each day. They also need well-drained soil, as tubers can rot in wet conditions. Ensure your soil is loose and enriched with organic matter; adding sand can improve drainage.
Staking Dahlias Early
Dahlias grow quickly and can become floppy if not properly supported. To prevent this, stake them early. Place a stake in the ground at the time of planting your tubers. This avoids damaging the tubers and ensures they have adequate support as they grow. You can add additional stakes later if needed.
Controlling Plant Size with Pinching
Pinching is an effective way to manage dahlia plant size. By regularly removing the growing tips or side shoots, you can keep the plants compact and reduce their tendency to flop. This also promotes bushier plants with more blooms.
Encouraging Growth Through Deadheading
Deadheading, or removing spent flowers, is crucial for dahlias. It keeps the plants looking tidy and prevents them from producing seeds, which encourages more buds and flowers. Regular deadheading extends the blooming period significantly.
Watering Dahlias
Dahlias require moderate watering. They are not drought-tolerant, but they also do not need excessive water. Water them and wait until they start to wilt slightly before watering again. It is better to err on the side of underwatering than overwatering.
Preventing Mildew and Fungus
While dahlias are generally disease-resistant, they can be susceptible to mildew and fungus in humid conditions. To prevent this, water from below rather than above to keep the leaves dry. If problems persist, use an all-purpose fungicide.
Protecting Against Insects
Dahlias are relatively resistant to pests, but Japanese beetles can sometimes be an issue, as they feed on the flowers and leaves. You can remove them by hand or use an insecticide. Additionally, bees and wasps often rest in dahlia blossoms. To avoid stings, gently shake the flowers before cutting.
By following these guidelines, you can enjoy vibrant and healthy dahlias in your garden.