Stop pruning your hydrangeas at random: gardeners explain the “two stems to spare” method for huge blooms next summer

On a grey Saturday in late February, somewhere between the last of the frost and the first proper hint of spring, I watched my neighbour march into her border with a pair of secateurs and the confidence of a woman on a mission. Ten minutes later, her hydrangea was a neat, brutal bundle of sticks. “You’ve got to cut them right down or they don’t flower,” she called over the fence. I smiled, nodded… and quietly did the opposite.

A few months on, her shrub produced a polite scattering of blooms. Mine, left looking slightly unkempt for longer, exploded into ridiculous, hat-sized flowers. The difference wasn’t fertiliser, or some secret compost tea. It was a simple pruning habit old gardeners mutter under their breath: always leave two stems to spare.

Hidden inside that slightly cryptic phrase is the reason so many of us end up with sulking hydrangeas instead of the mop of colour we were promised on the plant label.

Why random pruning is quietly ruining your hydrangeas

Hydrangeas look tough, but many of them are delicate about where their flowers come from. Mopheads and lacecaps – the classic big, round-flowered types – make next summer’s flower buds on this year’s stems, often by late summer or early autumn. Hack those stems to the ground in winter and you’ve essentially binned next year’s show.

That’s why some shrubs seem to have “off years” after a hard prune. It’s not bad luck; it’s timing. We clip away the very wood that’s holding the flower buds, then wonder why nothing much happens in July.

Let’s be honest: most of us prune hydrangeas when they annoy us. Brown flower heads, floppy stems, a vague urge to “tidy the garden before spring” – out come the secateurs and off go the branches, more or less at random. It feels efficient. It’s also exactly how you end up with a beautifully shaped shrub and almost no blooms.

The “two stems to spare” rule is gardeners’ shorthand for slowing down, looking closely, and only cutting what the plant can afford to lose. It’s less work than it sounds, and it gives you permission to stop attacking your hydrangea like an overgrown hedge.

What the “two stems to spare” method actually means

Different gardeners explain it slightly differently, but the heart of the method is this: every time you’re tempted to chop, make sure you leave at least two strong, bud-carrying stems untouched to do the flowering for you.

In practice, it breaks down into two simple ideas:

1. On each flowering stem:
   When you remove last year’s dead flower head in late winter or early spring, only cut back to just above the second pair of healthy fat buds. You “spare” those two pairs of buds so they can grow on and flower.

2. On the whole shrub:
   When you’re thinning out old wood, never take everything. For every old, tired stem you remove right down at the base, leave at least two strong, younger stems in place. That way the plant always has enough older wood carrying flower buds, plus new shoots coming through for future years.

It sounds almost too simple, but that’s the point. You’re swapping guesswork for a small, consistent rule. Instead of shearing the whole plant to knee height, you’re editing: one stem at a time, two stems to spare.

Step-by-step: using the rule on your hydrangea this year

You don’t need a degree in horticulture. You need sharp secateurs, ten minutes, and the ability to count to two.

1. Wait for the right moment
   In the UK, resist the urge to prune in autumn. Leave those papery flower heads on over winter; they help shield the buds from frost. Aim to prune in late March or early April, once the worst cold has passed.

2. Start at the top – deadhead with care

   • Take a stem with an old, brown flower on the end.
     
   • Slide your fingers down until you find the first and second pairs of fat, green buds below the old flower.
     
   • Cut just above the second pair.
     
   • Move on to the next stem and repeat.
     

You’ll notice you’re not cutting very far down at all. That’s the idea.

1. Stand back and spot the oldest stems
   Once the shrub is deadheaded, step back and look at the base. Older stems are usually thicker, more barky, sometimes with peeling bark; young ones are slimmer and fresher.

2. Renew without scalping

   • Choose up to a third of the oldest, least productive stems.
     
   • Cut those selected stems right down at ground level.
     
   • For every stem you remove, make sure there are at least two younger, strong stems nearby that you’re not touching.
     

That’s the “two stems to spare” part that keeps the flower show going.

1. Stop before it feels “perfect”
   Hydrangeas don’t need to look like topiary. Once you’ve deadheaded and removed a few old stems, stop. The plant should look slightly wild, not brutally tidy.

Why sparing two stems gives you bigger, better blooms

When you only take the top off each flowering stem and remove just a few old canes at the base, two helpful things happen.

First, you protect the flower buds that are already sitting on those stems. Each spared pair of buds has the energy and maturity to produce a fat, confident flower head. Hard pruning forces the plant to spend the season rebuilding basic structure instead of investing in blooms.

Second, you spread the plant’s energy across a sensible number of stems. A shrub left completely unpruned for years ends up with a thicket of weak, crowded growth and smaller flowers. By removing just a fraction of the oldest stems each spring, you open up light and air, and the remaining shoots can bulk up and carry larger heads.

The result is a plant that looks like it’s been in the ground for years – because it has – but still behaves like a vigorous youngster. You’re not starting again every spring. You’re editing an established framework so the plant can do what it’s been planning to do all winter.

A quick note on different hydrangea types

Not all hydrangeas follow the same rules, but the “two stems to spare” idea still helps as a safety net.

Hydrangea type	Flowers on	How to use the rule
Mophead & lacecap (macrophylla, serrata)	Old wood (last year’s stems)	Essential: deadhead to second pair of buds, remove only a few oldest stems at base.
Panicle (paniculata) & ‘Annabelle’ types (arborescens)	New wood (this year’s stems)	Can be pruned harder, but still leave a couple of strong framework stems per clump for stability and bigger heads.
Climbing hydrangea	Mainly old wood	Light thinning only; remove a few old stems, sparing plenty of flowering shoots.

If you’re not sure what you have, treat it like a mophead and err on the side of caution for a year. The plant will forgive you. A hard prune at the wrong time is much harder to undo.

Common pruning mistakes – and the simple fixes

Most hydrangea disasters come from the same handful of habits. You don’t need a complex pruning chart; you just need to dodge these.

• Cutting everything to the same height
  Treating the shrub like a hedge removes flower buds and kills the natural shape.
  Fix: Work stem by stem. Different heights, same two-stem rule.

• Pruning in autumn “to tidy up”
  Autumn cuts expose tender buds to frost and remove wood that would flower next year.
  Fix: Leave the brown heads on as winter hats. Do your pruning in spring.

• Removing all the old stems at once
  It’s tempting to “rejuvenate” a tired plant with a clear-out, but you may sacrifice a year or two of flowers.
  Fix: Take out no more than a third of the oldest stems per year. Always leave at least two good ones nearby.

• Being afraid to cut anything at all
  The opposite problem: years of no pruning can leave a tangled, flower-light shrub.
  Fix: Start small. Apply the method to one side of the plant this year, the other side next year.

Tomorrow morning: what to actually do in your garden

If your hydrangea is outside the back door, looking slightly miserable and twiggy, you don’t need to plan a full “gardening day” to sort it. Ten focused minutes is enough.

• Walk up to the shrub with your secateurs and pick five stems.
  
• On each, remove the old flower head to just above the second pair of buds.
  
• Choose one obviously old, woody stem at the base and cut it out completely.
  
• Stop. Make tea. Look at the shape.
  

Do the same again next weekend, or the weekend after. No drama, no big black bag of regret. Over a couple of springs, you’ll quietly reshape the plant without ever stripping it bare.

Hydrangeas are generous plants. They don’t need complicated feeding schedules or exotic sprays. They need sunlight, water – and pruning that respects the work they’ve already done. The “two stems to spare” method is less a trick and more a small act of restraint: a reminder to leave enough in place for the plant to get on with the show.

FAQ:

• I’ve already cut my hydrangea right back this winter. Is it ruined?
  Not necessarily. You may get fewer or no flowers this year on old-wood types, but the plant itself should recover. Let it grow freely this season, then start the “two stems to spare” approach next spring.
• How do I spot the pairs of buds I’m meant to leave?
  Look just below the old flower head for two fat buds directly opposite each other on the stem, then another pair below. Cut just above the second pair so both remain on the plant.
• My plant hardly flowers even though I don’t prune it. Will this method help?
  Yes. Lightly deadheading and removing a few of the oldest stems each year can let more light and energy reach the remaining shoots, improving flower size and number over time.
• Can I use this method on potted hydrangeas?
  You can. Just be even more conservative: deadhead to the second pair of buds and remove at most one or two old stems a year so the plant keeps a good framework in its limited root space.
• Should I feed after pruning to boost blooms?
  A balanced, slow-release fertiliser in spring and a mulch of compost around the base will support flowering, but it’s the careful pruning – not heavy feeding – that makes the biggest difference to next summer’s show.