A practical guide to dividing dahlia tubers with confidence

If you’re reading this, chances are you’ve caught the dahlia bug—and welcome to the club! Whether you’ve grown one plant or one hundred, you’ve probably looked at a dormant clump and wondered, Where on earth do I start?

The good news is that dividing dahlias isn’t nearly as scary as it first seems. Like any new skill, it becomes easier the more you do it. 

This guide is help to take the mystery out of dividing dahlia tubers. I’ll show you how to identify the important parts of a clump, explain why each piece matters, and walk you through the process step by step.

Before You Make the First Cut

Before reaching for your secateurs, it’s worth taking a moment to understand what you’re working with.

Freshly lifted clumps can look intimidating. Some are neat and tidy, while others resemble a tangled bundle of tubers pointing in every direction. It can feel tempting to start cutting straight away, but spending a minite observing the clump will make the whole process much easier.

Begin by removing loose soil so you can clearly see the crown and where each tuber joins it. Good lighting makes an enormous difference, especially when searching for eyes.

I like to wash my tubers before dividing.

Remember, you’re not trying to cut down to every tuber on the clump. Your goal is to create healthy, viable divisions that have the best chance of growing into strong, productive plants.

Each Tuber needs part of the crown neck and body

The Tools I Use

One of the questions I get asked all the time is, “What tools do you use?” The good news is you don’t need a shed full of fancy equipment.

Here’s what’s on my bench every time I divide dahlias:

• Felco 322 harvest snips – These are my go-to for making precise cuts and getting into tight spots around the crown. They’re lightweight, incredibly sharp, and perfect for detailed work.
• Felco No. 2 secateurs – A true classic. I use these for thicker stems and tougher cuts where I need a bit more strength.
• Methylated spirits – I regularly sanitise my tools with methylated spirits, especially when moving between clumps. Clean tools are one of the simplest ways to help reduce the risk of spreading disease.

My biggest tip? Keep your blades sharp and keep them clean. A sharp blade makes cleaner cuts, causes less damage to the tuber, and makes dividing far easier.

Learning to Spot the Eyes

If there’s one skill every dahlia grower wants to master, it’s finding the eyes.

The eyes are the tiny growing buds (pimples) that will produce next season’s shoots. Without an eye, a tuber cannot grow into a new plant.

The challenge is that eyes don’t always make themselves obvious. Some varieties produce large, easy-to-see eyes, while others have tiny eyes that almost disappear into the crown. Temperature, storage conditions and the time of year can also influence how visible they are.

The important thing to remember is that eyes form on the crown—not on the tuber itself.

Once you begin recognising where eyes naturally appear, you’ll stop searching the entire clump and instead focus your attention exactly where it matters.

Don’t be discouraged if they seem impossible to find at first. Every clump you divide teaches your eyes what to look for, and before long you’ll start spotting them almost instinctively.

Every Part Has a Purpose

A dahlia clump is made up of several different parts, and each one plays an important role.

The tuber acts as the plant’s food storage. It holds the energy needed to fuel those first shoots in spring.

The neck is the narrow connection between the tuber and the crown. Although it may look insignificant, it forms the vital link that allows water and nutrients to move between the tuber and the new plant. If the neck is snapped, the tuber is no longer viable.

The crown is where all the magic happens. This is where the eyes develop and where new growth begins each season.

Understanding how these three parts work together makes dividing much less confusing. A healthy division needs all three: a tuber, an intact neck, and a piece of crown with at least one viable eye.

Once you understand this simple combination, assessing a clump becomes much more straightforward.

Let’s Divide a Clump

Now it’s time to put everything together. Start by identifying the crown and locating the eyes. Decide where each division will be made before making your first cut.

Work slowly and deliberately. There’s no prize for finishing quickly, and careful cuts almost always produce better divisions.

As each tuber separates from the clump, check that it still has an intact neck and a portion of crown with a visible eye attached.

If a tuber doesn’t meet those requirements, it’s unlikely to produce a new plant, no matter how large or healthy it appears.

Remember that every clump is different. Some divide neatly into individual tubers, while others naturally produce larger divisions containing two or three tubers. Both can be perfectly acceptable if they contain everything needed for healthy growth.

Dividing isn’t about perfection—it’s about having all the anatomy you need for a new plant to grow

Tricky Clumps & Common Mistakes

Not every clump likes to cooperate.

Some varieties produce masses of tightly packed tubers, while others create twisted crowns that seem almost impossible to separate. These clumps simply require a little more patience.

One of the most common mistakes beginners make is keeping every tuber, even when it doesn’t have an eye. It’s understandable—throwing away a perfectly plump tuber feels wrong—but unfortunately size alone doesn’t make it viable.

Another common mistake is accidentally snapping the neck while handling the clump. A broken neck usually means the tuber can no longer support new growth.

And finally, don’t worry if your first few clumps aren’t perfect. Every grower has accidentally cut through an eye or lost a good tuber while learning.

Good Luck!!

Dale 🤓🌸