Growing Dahlias for Cut Flowers
Expert advice on growing dahlias for cut flowers, including tips on taking basal cuttings, starting tubers, and caring for the plants.
Just a few dahlias planted in spring can fill borders with beautiful colour in late summer and early autumn. There are thousands of dahlia varieties, and breeders come up with new beauties every year.
Growing Dahlias for Cut Flowers
Dahlias are a must-have for any garden, with their jewel-like colours and lush, luxuriant growth. Rachel Siegfried of Green & Gorgeous cut flower growers in Oxfordshire shares her advice on growing healthy dahlias for robust cut flowers over the longest period.
Taking Basal Cuttings
To take basal cuttings, cover dahlias tubers in compost-filled vegetable crates lined with landscape fabric in mid-February to March. Place on a heated mat at 18°C in the greenhouse and keep moist. When shoots develop two- to three-leaf joints, use a clean, sharp knife to take cuttings from near their base. Trim below a leaf joint, dip in rooting powder, and plant in pots or modules filled with free-draining seed compost and keep humid. Once roots develop, pot on regularly until it’s time to plant out.
Caring for Dahlias
Water dahlias regularly, and feed bi-weekly with high-potash feed. Deadhead weekly to promote new flowers. The dahlia’s worst enemies are slugs, snails, and earwigs, so take appropriate precautions to keep these at bay.
Overwintering Dahlias
Dahlias can be overwintered either by lifting or leaving them in. Lifting is generally the better option for quality cut flowers since tubers have more vigour and produce more and better blooms.
Lifting Dahlias
To lift dahlias, cut stems back to 10cm after the first frost, carefully lift, discard damaged tubers, clean, and label. Invert to drain and completely dry the tuber for two weeks before storing. Pack in crates on a layer of sterile potting compost and cover with a sterile vermiculite duvet. Store in a frost-free, cool, dark place until February, checking intermittently and removing any with rot.
Choosing Dahlias for Your Garden
Forget the enormous football-sized blooms of horticultural shows and think more of Christopher Lloyd and his vibrant dahlia combos at Great Dixter or consider Sarah Raven and the signature creative colour mixes that feature in her flower arrangements.
The Best Cactus Dahlias
Among the best for growing in borders are the cactus dahlias. These varieties are perfect for adding a pop of colour to your garden and can be grown in a variety of conditions.
The best cactus dahlias include:
