Undisputed stars of the flower bed, knowing how to deadhead dahlias is essential to keep these showy and flamboyant flowers blooming for as long as possible.
There is such a wide variety of dahlias to enjoy that they can have a starring role in post-season flower bed ideas. Choose from a range of colours, varying flower sizes and shapes, multi-coloured flowers or black leaves. Growers around the world continue to introduce additional variations and combinations to keep up with trends – in fact, the range of sizes and colors is virtually unmatched in the flower world. With the right care and attention, dahlias can continue to bloom from summer to winter.
Once you learn how to grow dahlias, you will quickly become obsessed with them after you see the first flowers unfold. So to prolong your enjoyment of these bloomers, read on to find out how and when to deadhead dahlias.
How to deadhead dahlias
If you are new to dahlia growing, you will first have learned when to plant dahlias for best results and you have learned step by step how to plant dahlia tubers. When your flowers start to appear in mid-summer, it’s time to learn how to deadhead dahlias.
Dahlias make wonderful cut-and-come-again blooms if you’re planning a cut flower garden because they bloom for months on end. Deadheading and picking these priceless late summer flowers regularly encourages them to keep producing more flowers right up until the first frost.
As with deadheading or pruning flowers, be sure to have the right equipment on hand to avoid damaging the plants. “You need a sharp knife or pruning shears for dead dahlias,” explains Tye Abdul, CEO of Abdo Florist (opens in new tab).
What is deadheading?
Deadheading dahlias involves removing only the spent flower buds. This does not harm the plant, but instead, by removing the dying flowers, you encourage the plant to put its energy into root and flower development.
‘Unless you are leaving seed pods to ripen on the plants for breeding purposes or collecting seeds, make sure to remove all spent flowers so the plants continue to put energy into flower production rather than making seeds. This practice is an important ritual in the cutting garden if you want a steady flow of beautiful flowers for the longest time,” explains Erin Benzakein, author of Florets farm’s discovery of dahlias (opens in new tab).
Where do you cut when you cut dahlias?
Where you cut when deadheading dahlias is important.
When your dahlias begin to bloom, inspect the flowers at least once a week to check for dead or dying flowers. You want to remove flowers when they start to wilt and any that are completely wilted and starting to form seed pods.
You’ll quickly discover when you learn to deadhead dahlias that it’s easy to identify spent flowers where the petals are wilting and starting to fall off. But if you miss that stage, it’s not always so easy to identify which buds you need to kill and which ones are about to bloom.
“It can sometimes be difficult to distinguish used buds from new ones – the key is in the shape of the bud. If it’s pointy – and a bit squishy – it’s gone; if it’s round and cheerful, it’s a new bud,’ explains Pippa Blenkinsopp, Houses and gardens Content editor and expert in growing dahlias in her beautiful flower garden.
Once you’ve identified which flowers are wilting or budding, deadhead, then use a pruner to cut the flower stem as its intersection point for a leaf. This will encourage more flowers and avoid the sight of flowerless stems sticking out everywhere.
Where do you deadhead dahlias if a stem has more than one flower?
‘The tricky part of deadheading dahlias is when there are multiple heads on a stem. If one of the flowers has passed, you have two choices: You can either remove the dead flower by cutting back to the bud joint and let the other buds bloom, or you can make the decision to cut further down the stem. by the next set of leaves,’ explains Pippa.
‘If the flower stems are short, I often tend to cut the dahlia back further down the stem to encourage longer new shoots for cutting back to create a summer flower display. Having one of the short flowers cut from a three-headed flower stem may not look good in a vase. But if you’re growing dahlias for border color for the garden’s color schemes, then it might not be a problem,’ she adds.
When should I deadhead dahlias?
When you should deadhead dahlias will depend on when they start to bloom, which will vary depending on the hardiness zone where you live.
‘It helps if you deadhead dahlias every few weeks to keep them blooming,’ explains Tye Abdul, although in high season it can increase to every few days.
You should deadhead dahlia flowers when they have wilted and the buds are spent.
How do I keep my dahlia in bloom?
The best way to keep your dahlia blooming is to deadhead spent blooms regularly, and also cut flowers for flower displays around the house, which will encourage your plants to produce more flowers.
“Like all plants, dahlias are prone to bacterial, viral and fungal diseases when stressed,” explains Erin Benzakein, so be sure to keep your plants happy and healthy by planting in the right location, allowing plenty of air flow, and nurturing and watering them correctly. Where you encounter pests or diseases, ‘I advise you to use organic methods as much as possible. Cultivation obviously requires more effort and attention, but pays off in the quality of the flowers, adds Erin.
However, deadheading is one of the most crucial elements in keeping your dahlias blooming for longer.