How to double your dahlias – and get bumper blooms without buying any more plants

When I think of a flower I could never be without in my cutting patch, it would undoubtedly be dahlias. There are so many wonderful varieties of these magnificent flowers, some that form perfectly symmetrical pom pom spheres, and other, single petal varieties with glorious dark foliage.

There are a few handy tips to successful dahlia growing. These include deadheading spent flowers during the growing season to prolong flowering, as well as overwintering dahlias and storing the tubers properly to replant them the following spring. And, another very useful trick to ensure you get more blooms for your buck from these summer-flowering favorites is to pinch out their growing tips.

I’ve grown dahlias - both in beds and containers - for the best part of a decade, and ever since I learned the trick of pinching out I’ve been able to produce more flowers on every one of my plants. Here, I share with you my top tips for getting more out of these glorious garden blooms.

What is pinching out?

Pinching out is when we remove the growing tip from a plant in order to encourage side shoots to grow. By pinching out plants, the aim is to create larger, bushier plants with more flowers and crops on them, that will hopefully flower for even longer in the season.

It can feel very counterintuitive when you first have a go at pinching out, especially when a plant looks like it is growing away very happily. Why would you snip the top off it? I remember vividly having to force myself to do it initially, but once you see the results and understand how it benefits plant growth, you’ll be wholly converted.

When to pinch out dahlias plants

You need to wait until your dahlia plants have at least three pairs of leaves coming off the central stem before starting to pinch out the growing tips. This will have given your dahlia enough time to establish, and grow strong and heathy foundation foliage.

Depending on the variety of dahlia you are growing, this will usually be when the plant is 10 inches tall - possibly more.

As soon as you see three healthy sets of leaves you can pinch out the central growing tip. Any earlier and you will affect its future growth. However, each plant needs enough time in the growing season to recover and produce side shoots, so don't leave it too much later either.

How to pinch out dahlias

Always use clean and sharp pruning tools for the job to ensure you get a sharp cut, and don’t risk passing on any diseases to your plants.

You can simply use your fingers for the job if your plants are not too large, but I always prefer the clean cut you get from snips like these, from Amazon, and they are so easy to use.

Take a look at your plant and identify the central bud. This should be easy to see, as it will be growing at the top of the main stem. You can make sure you are looking at the central stem as all the other sets of leaves will be growing out from it.

Take your snips and carefully cut out the tip, just above a set of leaves. This will encourage the plant to divert its energy and for side shoots to sprout. For every set of leaves on the plant, you will get two more stems, which equates to up to four times more flowers from each dahlia tuber.

So now you can simply watch as your flowers multiply. The new, lateral stems should develop in as little as two days. The pinching out process does put the flowering time back by a week or so, but it also prolongs the season, as you will have so many more flowers on each plant blooming at different times.

FAQs

What happens if I don’t pinch out my dahlias?

If you don’t pinch out your dahlias they will still grow and bloom beautifully, but you will usually only get two or three flowers at the top of your plant. This is perfectly fine, but if you want more flowers on your plants, pinch out to encourage those side shoots.

Can pinching out damage dahlias?

Pinching out does not damage dahlias, or any other plants you use this technique on. The only dangers are pinching out too early, which could jeopardize the future health of the plant, and not cutting in the right place.

You can also pinch out a bit too late, when the growing tip has become much wider. As dahlia stems are hollow, this could cause damage if too much water or pests settle inside the stem.

Getting more flowers from your plants is a goal for all gardeners, and by using this simple, free technique you can really make the most of your dahlias. For more dahlia care and propagation tips, you can read our guides on how to harvest dahlias seed and how to plant dahlia tubers.