Deadheading dahlias: what to do when your blooms fade

Deadheading dahlias is super simple and means you will get more gorgeous blooms from your plants.

A real garden favorite, showy dahlias come in a kaleidoscopic range of colors and a multitude of flower shapes. Learning how to grow dahlias is easy, too. Once you get into the habit of growing them, nothing quite compares in terms of adding bold color and impact to your yard in summer. And you'll want to keep the show going for as long as you can.

With plenty of tips from the experts, we explain how to deadhead dahlias the right way for better, longer-lasting blooming.

6 simple steps to deadheading dahlias

Deadheading flowers in the correct way keeps your blooms looking lovely for longer.

'Unless you're leaving seedpods to mature on the plants for propagation purposes, be sure to remove any spent blooms so that the plants continue to put energy into flower production, rather than making seeds,' says dahlia expert Erin Benzakein, founder of Floret Flowers in Mount Vernon, WA. 

'This practice is called deadheading and is an important ritual in the cutting garden if you want a steady stream of beautiful blooms for the longest amount of time.' 

It's easy when it comes to how to deadhead types of dahlias. Just follow these simple steps:

1. Make sure your best secateurs or scissors are sharp and clean so you don't damage the stems when you start deadheading.
2. Check your plants over for any dahlia flowers that have faded, are curling over, have become tinged with brown, or have dry and papery petals. 'If you don't pick dahlia flowers often for arranging in the house, they will need regular deadheading,' says dahlia expert Sarah Raven.
3. Remove any faded blooms with a clean snip. 'To deadhead, follow the flower stem down and cut above the first pair of leaves you meet,' adds Sarah. 'This will promote more flower formation.' Don't simply cut off below the spent flower. This will leave a flowerless stem that looks ugly, and won't promote flowers to grow back, either. 
4. If your dahlia plants have become overgrown or leggy, cut the flower stems back further to improve the shape.
5. At the same time, check for any dry, yellowing, or withered leaves and tidy up the foliage too. This will also improve the overall look of your dahlia plants.
6. Remove and dispose of the old flower heads and pruned leaves after each pruning session because old plant material can attract insects and spread plant diseases.

How to deadhead dahlias in a pot

Dahlias grow well as part of your container gardening ideas as long as you use a good potting mix, fertilize regularly, and deadhead them in exactly the same way as you would if they were in the ground, by following our step-by-step guide above.

If you choose a compact variety that blooms abundantly you will need to be extra vigilant when it comes to deadheading dahlias in pots. 'We love the compact variety of a dahlia called "Tropical Breeze",’ says Thompson & Morgan’s horticultural expert Sue Sanderson. 'It's perfect for filling pots.'

Deadhead faded flowers regularly to encourage more blooms, and keep the pot where you can see it so deadheading doesn't fall off your agenda. 

When is the best time for deadheading dahlias?

Leave it too late and deadheading dahlias can get tricky. All the petals from your faded dahlias will have fallen off, leaving behind something that looks confusingly like a bud. 

There's an easy trick for working out what's the nub of a spent flower and what's a new bud. Just remember if the stem has more of a pointed shape on the end of it instead of being rounded like a bud then it's already done its stuff and is finished. These cone-shaped, spent dahlias will need removing straight away.

How often should you deadhead your dahlias?

To get prolonged flowering, you need to deadhead regularly throughout the blooming season. So, as soon as petals pass their peak and start to brown and wrinkle, take action. Get out your secateurs and start snipping them off right away.

After the initial deadheading, it's really important to inspect your dahlias at least once a week for dead or dying flowers and tidy them up.

Picking fresh flowers for indoor displays will also encourage more blooms. 'Dahlias love and need to be cut to prolong their flowering period and you should be bold and reach deep into the plant to cut a long stem to encourage the growth to regenerate from low down in the plant,' says Camila Klich and Marianne Mogendorff of the Wolves Lane Flower Company. 'If you're planning to harvest a lot of dahlias on a specific date, be ruthless with your deadheading roughly five days before to give them time to regenerate their blooms.'

That's it – everything you need to know on how to deadhead dahlias so that you can grow productive, healthy plants that take center stage as part of your cutting garden flowers.