Gardeners swear by this one trick to double your dahlias for a mass of beautiful blooms this year

Do you know how to double dahlias? It might sound like a spell, but, to be honest, gardening has always been that way – even something as simple as knowing when you should plant dahlias directly into the ground is key to making them bloom.

Still, doubling your dahlias so you have more flowers than you started with feels... well, it feels a little more magical than, say, the semantics of sussing out how to grow dahlias in pots.

Of course, if you're already a master at pinching out plants, you'll likely possess all the skills you need to make that dreamy mass of dahlias a reality. And if not? Don't worry; we're here to help...

How to double dahlias

It's little wonder that so many of us are keen to learn to double dahlias; with dramatic blooms the size of dinnerplates, they're one of those plants that deliver big impact at a small cost every time.

'Dahlias are one of the most popular garden plants and provide an abundance of flowers from summer through to the first frosts. There are so many varieties and colours to choose from and are very easy to grow with some care and attention,' says Morris Hankinson, director of Hopes Grove Nurseries.

Morris Hankinson

Morris Hankinson is the founder and managing director of Hopes Grove Nurseries Ltd, the UK’s only specialist grower-retailer of hedging plants. He established the thriving business in 1992, shortly after graduating with a Commercial Horticulture Degree from Writtle College, Essex.

What you'll need

So, what equipment do you need to double dahlias? Honestly, very little indeed...

• A pair of protective gloves (we rate the Niwaki Gardening Gloves, £6 at John Lewis)
• Some clean, sharp gardening scissors, like the Darlac Ergo Gardening Snips, £16.99 from Amazon
• A gorgeous dahlia, of course: the Dahlia 'Vancouver', from £14.39 for a 3-litre pot at Crocus, for example, or the Dahlia 'Café au Lait', £16.95 for a 3-litre pot from Sarah Raven both fit the bill

Step-by-step guide

Once you've gathered all your tools to hand, it's time to double dahlias like a pro. And, trust us, you really will be doing it like a pro before you know it; it's that easy!

1. Pinch out your dahlia

It might go against every instinct in your body, but the best way to multiply flowers is to start pinching in earnest.

'To increase the number of flowers on each dahlia plant, one of the first things to do is to pinch out the growing tip,' says Morris.

'This might seem counterintuitive, but by removing this from younger plants after they have reached about 30cm tall, you'll stimulate more bushy growth. And more growth means more flowers.'

If you're a little at a loss, the trick is to 'take the top of the growing tip down to just above a node or lower leaves,' explains Morris.

Always make sure to use a clean, sharp pair of small snips for the job.

2. Deadhead regularly

If you want to not just double dahlias but keep dahlias blooming, too, then you will also need to deadhead.

'Deadheading is really important with dahlias because as soon as a flower is past its best, the plant will put energy into producing seeds instead of flowers,' says Morris.

'Plus, if you deadhead regularly, you can take plenty of fresh flowers for a vase.'

3. Keep them hydrated

Whether you're planting in your garden borders or have been planting dahlia tubers in pots, you will need to water your dahlias for them to thrive.

'Keep watering, especially in dry conditions,' says Morris. 'If the soil hasn’t been mulched, they may also need an extra feed every couple of weeks during flowering.'

'A balanced fertiliser early in the season, followed by a high-potash feed once buds start forming, supports strong, productive plants,' agrees landscaper and gardening expert Steven Bell.

Steven Bell

Steven Bell is an experienced landscaper, with years of experience owning paving and gardening companies. Combining hands-on expertise with a deep appreciation for sustainable landscaping practices, Steven enjoys sharing his insights with readers to inspire their own green-thumb adventures.

'And, of course, staking taller varieties and ensuring plenty of light and airflow will keep them both healthy and visually striking,' he adds.

FAQs

How to double your dahlias?

If you want to learn how to double your dahlias, landscaper and gardening expert Steven Bell says it comes down to a few key practices – timing, technique, and overall plant health.

'Pinching out the growing tips when plants are around 20–30cm tall encourages bushier growth and leads to more flowering stems,' he says.

'It’s also worth noting that consistent deadheading throughout the season helps prolong flowering and promotes the development of more blooms,' he adds,

Which is the best dahlia?

Which is the best dahlia? It's a good question and, with so many dahlia varieties to choose from, Morris Hankinson of Hopes Grove Nurseries says it’s well worth looking for those which are known to produce a lot of flowers.

‘Bishop of Llandaff at Crocus, from £14.39 for a 3 litre pot has dark foliage and bright red flowers, Cafe au Lait at Crocus, from £14.39 for a 3 litre pot is a particularly pretty variety with large, off white/creamy flowers which look stunning in a vase, and Kelvin Floodlight at Crocus, from £5.49 for one tuber is a love it or hate it type with vibrant, yellow, dinner plate size flowers,' he recommends.

Of course, the best dahlia is obviously subjective; choose the one you love the most and think looks best in your garden... especially if you plan to double dahlias from it.

Now that you know how to double dahlias, all that's left to do is go forth and make the magic happen in your own garden. Good luck...