Spotlight On: Dahlias — The Powerhouse of the Late Summer Garden (And Why You Should Be Sowing Right Now)

If you only grow one flower this season, let it be a dahlia. And if you've always assumed you need to buy tubers to grow them — I have some very exciting news for you.

Let's start with something controversial.

I don't dig up my dahlias.

I know. I know. Every YouTube tutorial, every Instagram grid, every gardening book (especially from the northern hemisphere) will tell you that once flowering is over, you dig, you lift, you store, you label, you cram them into a box and wait for spring.

Reader, I do not do this. And for almost everywhere in Australia you don’t have to either.

A thick layer of mulch and walk away. That's it. Easy, lazy, and absolutely my kind of gardening.

I Am Not Alone In This (And I Have Receipts)

When I first started talking about this publicly, I braced for the pushback. And man, it arrived. See here. But then something unexpected happened.

Messages started flooding in from all over the world -North America, the UK, all over Europe, South America, New Zealand - and every corner of Australia - from growers saying they'd never dug their dahlias up either. Some of them were in genuinely cold and soggy climates.

And not just Floret. Professional flower growers from all over the globe raised their hands and said "only when we want to divide", or "only if we're selling them" and "only because we need the space for growing."

To the 'must-diggers': I have sources now.

We've all been loyally following advice without testing the premise - and it's been costing us time, effort, and money. A key thread in the hundreds of messages I received was that the tuber failure rate when digging up was as high if not higher than when they were left in the ground.

But I cannot say this loud enough - if you want to dig them up every winter, go for it. If it makes your heart sing, or connects you with your grandmother because that's what she did - whatever. If you want to, do it. My message is just: in most cases, you don't have to.

Dahlias: What They Actually Are

Before we go further, a quick love letter to the dahlia itself.

Dahlias are the absolute powerhouse of the late summer and autumn garden. While everything else is starting to wind down and look tired, dahlias are just hitting their stride - enormous blooms in every colour you can imagine, on stems strong enough to cut and bring inside, from January through to the first real frost.

They're a florist's best friend for a reason. And they are completely, absolutely, achievable in a home garden. Even a small one.

The Part Where I Suggest You Rethink Everything About How You Buy Them

Here's where I think it gets interesting.

Most people who want to grow dahlias go straight to tubers. And tubers are perfectly fine. But there's another way - and it's cheaper, more exciting, and sidesteps one of the most heartbreaking things that can happen in a flower garden.

I was watching an Instagram dahlia influencer (yes, that's a thing) recently, doing what he called a "dahlia audit." Thirty-five days after planting out his tubers, he was walking his rows and anywhere there was a gap - anywhere a dahlia should have been growing but wasn't - he was carefully digging down to investigate.

In the video, he uncovered a variety called Jabberbox. Completely rotted in the ground. He was at pains to point out: it came from a reliable supplier. It had looked perfect going in. And he'd paid $15 USD for it.

He said, almost in passing, that dahlia growing "is an expensive hobby."

It doesn't have to be.

The Maths (And It’s Satisfying)

Here's what growing dahlias from tubers can cost you. Twenty tubers at $15 USD each is around $440 AUD -all before a single flower has opened. Popular varieties run $30–$40 each for a single tuber. A clump? Up to $130. And with tubers, rot is always a risk, even with the best supplier, even when you do everything right.

One packet of seeds. Up to 50 plants. No mortgage required.

A packet of seeds and your time. A fraction of the cost. Suspense and excitement of mystery outcome included (see below).

But Wait — Can You Actually Grow Dahlias From Seed?

Yes. Emphatically yes.

Dahlias from seed? Isn't that the hard way? Aren't they usually grown from tubers?

They are. And we're doing it from seed anyway. Because it's cheaper, more exciting, and when they bloom you will absolutely be standing in your garden saying "I grew these myself."

Here's what makes seed-grown dahlias genuinely thrilling: every single plant you grow has never existed before. Not once. Not anywhere on earth. The genetics shuffle differently every time. You might end up with something spectacular - a colour combination, a form, a size - that no one has ever seen. You could accidentally become the breeder of the next dahlia superstar variety. Seriously.

And crucially: when you grow from seed, you do not experience tuber rot before the plant has even emerged. You don't do an audit thirty-five days later and find a rotted Jabberbox. You just... grow dahlias. Exciting, unpredictable, wildly satisfying dahlias.

You Need To Be Sowing Now

This is not a "maybe get to this one weekend" situation.

Dahlias from seed need a lead time to flower in their first season. Sow now - in winter - and you are perfectly placed for flowers from January through autumn. Wait too long and you're giving your plants less time to establish and less time to bloom.

The good news: the process is straightforward.

What are you waiting for?

If you think growing Dahlias from seed might be just the sort of rebelious act that gets you exicted, we do just this (and so much more) in The Flower Growing Year. More details about my 12 month beginner flower growing course here.