Your dahlias went in at the right time, they’re green and tall and honestly looking quite smug about themselves — so why isn’t a single bud showing? In June, dahlias should be gearing up for their first flush. But if they’re sitting there like stubborn teenagers, one mistake is almost certainly behind it. And the decent news is, you’ll fix it today, in about ten minutes.
Most likely, you skipped the pinch. Or — and I did this for three full years before someone finally shouted at me about it — you pinched too late, or not hard enough. Seriously. This is a non-negotiable step.
Pinching the growing tip when the plant is about 40cm tall forces the dahlia to branch out instead of bolting upward. Miss that window? The plant throws all its energy into a single weak stem. It’ll either flop over or produce one measly flower in late August. That’s a waste of time.
There’s a second culprit: nitrogen. And if you’ve been feeding with a general-purpose fertiliser — anything with a high first number on the NPK label — you’ve been telling the plant to shoot up leaves.
Lots of them. Beautiful, glossy, absolutely useless leaves.
Dahlias want phosphorus and potassium once they’re established, not nitrogen. My grandmother in the Vendée used to say feeding a dahlia nitrogen in June was like giving a racehorse a bread roll before a sprint. Useless calories.
And yes, overwatering is genuinely stalling bud development in a lot of gardens right now. Soggy soil around tubers causes the plant to prioritise root defence over reproduction. In my walled garden in Somerset, managing that clay can be a proper faff. Roots stressed by anaerobic conditions don’t signal “bloom now.” They signal “survive.”
Possibly. Eventually. But here’s what that looks like in practice: you’ll get one or two blooms in late September, just as the first frost warning appears. And you’ll stand in the garden at dusk feeling personally wronged. I know that specific feeling.
It smells like wet leaves and disappointment.
The real risk with unpinched dahlias? It’s structural. That tall single stem is properly fragile. One proper summer gust — and British summers do produce them, even in June — and it snaps. You don’t get a second chance with a broken main stem.
The tuber survives underground, yes. But your 2026 season for that plant? It’s gone pear-shaped. Seriously, don’t let this happen.
Persistent overwatering can also rot the tuber itself, which you won’t even notice until you go to lift it in autumn and find something that looks disturbingly like a wet sock.
If your dahlias haven’t been pinched and they’re under 60cm, do it now. Pinch or cut cleanly just above a leaf node, pulling off the top 8–10cm of the main stem.
Yes, it feels violent. Do it anyway.
If your plant is already over 70cm and un-pinched, don’t panic. Pinch anyway. You’ll expect a slightly later bloom set, probably mid-August rather than late July. Better late than a single floppy stem, isn’t it?
Earwigs. I know they’re not the most dramatic pest, but earwigs absolutely devastate dahlia buds the moment they appear. They work at night and leave ragged holes that look like slugs, but they’re not.
Trap them with upturned flowerpots stuffed with straw placed on canes near the plant — low-tech, free, genuinely effective.
Watch the lower stems for any soft, discoloured tissue at soil level. That’s dahlia stem rot, usually Botrytis, and it moves fast in humid June weather. The RHS has a clear guide on Botrytis identification if you’re unsure what you’re looking at. Catching it at 5cm of damage is very different from catching it at 20cm.
Right, and this surprised me when I first moved to Somerset — vine weevil grubs can attack dahlia tubers underground while the plant still looks healthy above ground. If your dahlia suddenly wilts for no apparent reason on an otherwise fine day, pull it gently. If the tuber crumbles, vine weevil is almost certainly the cause. Nematode treatment now, before the summer really kicks in, is your best prevention. Don’t overthink this. Just do it.
If your summer flowers are struggling more broadly, it’s worth reading about what June heat is doing to blooms right now — some of those causes overlap. You’re not alone in the faff.
Smart tip: Switch to tomato feed the moment your dahlias reach 40cm — don’t wait for buds.
Not if the plant is under 70cm. Pinch now and you’ll still get a full flush — it’ll just arrive a week or two later than if you’d done it in May.
Almost certainly a nitrogen-heavy feed combined with a skipped pinch. Lush green growth with no flowers, that’s the classic symptom. It’s screaming for attention.
Switch to high-potash feed immediately and pinch the growing tip.
In normal June conditions, twice a week maximum — once if your soil retains moisture well. Push a finger 5cm into the soil before watering.
If it’s still damp, wait another day.
Yes, but pinch now rather than hoping for the best. An un-pinched dahlia over 80cm produces fewer, weaker stems. Pinching even late in the season redirects energy more effectively than doing nothing. You’ll thank yourself.
