Expert Tips and Tricks for Growing Gorgeous Dahlias

Dahlias are one of the most rewarding flowers to grow, offering vibrant blooms in a wide range of colors and forms. While they’re not difficult to grow, a few expert tips can make a big difference in how full, healthy, and long-lasting your dahlias turn out. Whether you’re growing them for garden beds or cut flower displays, these tips will help you get the most out of every bloom.

Choosing the right dahlia varieties

Dahlias come in a wide range of forms, from large dinnerplate blooms to compact pompons. Choosing the right variety depends on your garden space, climate, and whether you’re growing for cutting, containers, or borders:

For Beginners: Try reliable favorites like ‘Bishop of Llandaff’ (dark foliage, red blooms) or ‘Thomas Edison’ (classic purple).
For Cutting: Look for long-stemmed varieties with excellent vase life, such as the famous creamy-blush ‘Café au Lait’ or the durable red ball dahlia ‘Cornel’.
For Containers: Stick to shorter, compact bedding varieties like the ‘Gallery’ series (specifically bred for pots) or ‘Park Princess’ (a stunning pink cactus type).

When and where to plant

Dahlias should be planted outdoors only after the danger of frost has passed, typically in late spring. They need a full sun location that receives at least six hours of direct light daily. In cooler regions, starting tubers indoors a few weeks early can give you a head start on the season.

Preparing the soil for success

Dahlias thrive in loose, well-draining soil with a neutral to slightly acidic pH. Mixing in compost or aged manure improves soil structure and provides nutrients for strong growth. If your soil holds too much moisture, consider adding sand or planting in raised beds to improve drainage.

Planting dahlias correctly

Planting dahlias correctly provides a strong foundation for healthy growth and consistent flowering throughout the season, helping plants establish well from the outset and reducing stress as they develop. When this early stage is handled properly, dahlias are better equipped to respond to ongoing care and environmental conditions, making them easier to manage and more reliable in performance.

Dig: Go about 4 to 6 inches deep.
Space: Place tubers 18–24 inches apart.
Position: Lay the tuber horizontally with the “eye” facing upward.
Wait: Cover with soil but do not water until you see green shoots poking through the ground.

⚠️ Critical Rule: Excess moisture before the plant has leaves can cause the tuber to rot. Be patient to avoid killing the plant or stunting growth before it has had a chance to establish itself.

Care Routine: Water, Feed, Support

Watering: Once the plant is established, water deeply 2–3 times per week. Feeding: Use a low-nitrogen fertilizer monthly. (Too much nitrogen = lots of leaves, very few flowers). Staking: Tall varieties are top-heavy! Install a stake, tomato cage, or grid system at the time of planting so you don’t accidentally stab the tuber later.

Pinching and deadheading for more blooms

Pinching back the central stem when the plant is about 12 inches tall encourages bushier growth and more flowers. Removing spent blooms throughout the season helps redirect energy into new buds. Regular deadheading also keeps plants looking tidy and prolongs the flowering period.

Common problems and how to avoid them

Dahlias can attract unwanted guests like aphids, earwigs, slugs, and spider mites.

Avoid: Overhead watering, which encourages fungal issues.
Prevention: maintain good airflow to stop powdery mildew.
Treatment: Use neem oil, insecticidal soap, or hand removal.

Cutting and arranging dahlias

Cut dahlias in the early morning or late evening when the stems are hydrated. Select blooms that are fully open, as they do not continue to open after cutting. Place stems immediately into warm water and let them condition in a cool room for several hours before arranging.

End-of-season care and overwintering

When the first frost turns the foliage black, the season is over.

Cut Back: Trim stems to a few inches above the soil.
Dig Up: Carefully lift the tubers and let them dry for a few days.
Store: Keep them in peat moss or sawdust in a cool, dry, frost-free spot (40-50°F).

(Note: In warmer zones, you may be able to leave tubers in the ground if the soil drains well!)

Conclusion

With the right care and a few expert techniques, dahlias can deliver an unforgettable display from midsummer through fall. From planting and pinching to feeding and storing tubers, each step plays a role in your plant’s success. Use these tried-and-true tips to enjoy a garden full of stunning, show-quality dahlias season after season.