Potted Dahlias: How to Plant, Care for and Overwintering
With their colourful flowers, dahlias are a highlight in the garden – but they also look great in pots. Choosing the right variety, planting time and care are all important to ensure your potted dahlias bloom. Here is everything you need to know!
Which dahlias are suitable for pot planting?
Not every dahlia will thrive in a pot. Low-growing varieties with a compact habit are particularly suitable. Here are a few recommended varieties:
🌿 Mignon Dahlia: Small, bushy plants growing to a height of 50cm with single flowers, e.g. ‘Happy Single Wink’ or ‘Bishop of Llandaff’.
🌿 Gallery Dahlia: Ideal for containers as they only grow to 10 – 15 in, e.g. ‘Gallery Art Deco’.
🌿 Topmix Dahlia: Reaching a height of up to 20 in, they are very compact and free-flowering, e.g. ‘Topmix Red’.
🌿 Ball Dahlia: Small varieties such as ‘Bantling’ or ‘Little Robert’ can grow to a height of 35 in and produce impressive flowers.
Planting dahlia tubers: when and how?
The best time to plant dahlia tubers depends on your location.
- Planting in the house: Plant the tubers in smaller pots (about 2-3 litres) and place them in a bright, frost-free spot. This will bring the flowering season forward. From mid-May you can transplant the early dahlias into larger pots (at least 10-15 litres) or into the garden.
- Planting in the garden from mid-May: Tubers should not be planted directly in the garden until there is no risk of night frost.
The right pot for dahlias
Dahlias need space to grow vigorously. The ideal pot:
✅ At least 15 litres for smaller varieties, 20-30 litres for larger ones.
✅ Drainage holes to prevent standing water.
✅ A loose, nutritious substrate with compost or slow-release fertiliser.
Dahlias need a warm, sunny spot out of the wind to thrive. The pot should also be stable to prevent it from tipping over.
Caring for potted dahlias
To keep your potted dahlias blooming throughout the summer, they need regular care:
💧 Watering: Dahlias need plenty of water. Keep the soil evenly moist but avoid waterlogging.
🌿 Fertilising: Apply a liquid fertiliser every two weeks or a slow-release fertiliser every six weeks.
✂️ Pinch off the tips of the shoots when they are about 10 cm high. This process, known as pinching, makes the plants bushier.
✂️ Remove dead flowers: Cut off wilting flowers regularly, always above the last pair of leaves. This encourages new growth.
How to overwinter potted dahlias
Dahlias are not known to be hardy. If you think you can simply put the potted dahlias in a frost-free place and save yourself the trouble of digging them up, storing them and replanting them, you will unfortunately be disappointed. If the tubers remain in the ground during the winter, they can easily rot or dry out. It is therefore advisable to remove them from the soil and store them in a dry place out of reach of children.
- Dig them up after the first frost: When the foliage wilts, you can carefully remove the tubers from the soil. This is the case between October and November, depending on the region. Cut the foliage close to the ground and then carefully remove the tubers from the soil.
- Allow the tubers to dry: Leave the tubers to dry in a dry and frost-free place for a few days and then check them for damage. Throw away any damaged tubers.
- Store in a cool, dry place: Wrap the tubers in sand or newspaper and store at 40-50 °F.
- Replant in spring: You can start the tubers again from March.
With the right care, your potted dahlias will be a colourful highlight year after year! 🌸