Monty Don’s March Hydrangea Trick for More Flowers

Monty Don, the British television gardener, relies on a small yet vital March routine that can determine whether hydrangeas have a sparse or flower-filled summer. It is not about costly fertiliser or unusual varieties, but precise timing, highly selective pruning and a straightforward winter mulching technique.

Why March determines hydrangea flowers

Hydrangeas are among the most popular flowering shrubs in British gardens. Catalogue photographs show enormous flower heads, yet plants in borders often produce only a few blooms amid lots of bare green growth. One key reason is pruning at the wrong time.

The familiar mophead and lacecap hydrangeas (Hydrangea macrophylla) are particularly affected. They form their flower buds during the previous year, on what is known as old wood. Cutting these shoots back hard removes precisely the growth that should produce flowers in summer.

“The most important point is that many hydrangeas flower on last year’s growth. Pruning at the wrong time directly removes the coming display.”

March marks a delicate transition. Buds begin to swell and the plant emerges from winter dormancy, but frosty nights can still occur. According to Monty Don, this is when it is decided whether shrubs will later be covered in large flower globes or simply put on green growth.

Deadheading rather than cutting back hard: Monty Don’s spring mini-prune

A central issue is confusing two different jobs. To many people, cutting means simply cutting, but gardeners distinguish between removing faded flower heads and pruning back the plant properly.

• Deadheading: Removing old flower heads only, while retaining the shoots.
• Pruning back: Shortening or removing stems to control the plant’s size and shape.

Many people reach for the secateurs in winter to give hydrangeas a “tidy cut-back”. The result is that buds formed in the wood since last summer end up in the garden-waste bin. Monty Don therefore recommends a much gentler method, carried out specifically in March.

How to use the March trick step by step

Monty Don outlines a highly precise, almost minimalist pruning approach:

• Choose the right time: Late March is ideal, once the worst frosts have passed and buds are clearly swelling.
• Inspect the plant: Look along each shoot for the old, dried flower heads.
• Find the cutting point: Immediately beneath the brown flower head, there are usually one or two pairs of healthy, plump buds.
• Make the cut: Position the secateurs just above the uppermost strong pair of buds, removing only the spent flower head and the very worst few centimetres of the tip.
• Take out dead wood only: Cut fully brown, hollow or dead shoots close to the ground, allowing light and air into the centre.

The crucial point is that most of each shoot remains in place. The buds below the cut then grow strongly and carry the sought-after, substantial flower heads in summer.

“A single cut made a few millimetres above the right pair of buds can mean the difference between two flowers and a whole shrub full of colourful globes.”

What to consider for different hydrangea types

Not all hydrangeas respond to pruning in the same way. Anyone growing several varieties should be able to tell them apart:

Type	Flowers on	Recommended pruning approach
Mophead / lacecap hydrangea (Hydrangea macrophylla)	old wood	In March, remove only old blooms just above the first pair of buds; do not prune back hard.
Panicle hydrangea (Hydrangea paniculata)	new wood	Can be cut back more firmly in late winter or early spring, as flowers form on new growth.
Smooth hydrangea (Hydrangea arborescens)	new wood	A harder cut-back is also possible, often to just a few buds above ground level.

Monty Don’s “mini-prune” applies chiefly to classic garden hydrangeas that flower before June. A rule of thumb he has shared is: if a plant flowers before June, it is best not to cut it back hard in winter. This is exactly where most mistakes are made in home gardens.

Monty Don’s winter mulch routine for hydrangeas

Alongside careful pruning in March, Monty Don uses a second, very practical measure: a deep layer of organic mulch in winter. It may not look dramatic, but over time it acts like a wellbeing treatment for the roots.

How Monty Don mulches his beds

In January, when there appears to be little to do in the garden, he spreads a generous mulch layer around his perennials and shrubs. His recommendations are easy to apply in British gardens:

• Material: Well-rotted compost, mushroom compost, chipped bark, leaf mould, or a mixture of whatever is available from the garden.
• Depth: At least around 5 centimetres, though 10 centimetres is better. His principle is that a thick layer over half the area is more effective than a paper-thin covering across the entire plot.
• Distance: Do not pile mulch directly against the stem or base; leave a small clear collar to prevent rot.

This layer shields sensitive roots from sharp temperature changes, keeps the soil moist for longer and feeds soil organisms. For hydrangeas, this helps produce vigorous shoots in spring, making it the perfect companion to selective March pruning.

“Strong roots, settled soil and targeted pruning: this combination creates the basis for significantly larger and more numerous hydrangea flowers.”

Practical tips for home gardeners

Anyone wishing to try Monty Don’s approach in their own garden can begin with a single shrub. These points are useful in practice:

• Never prune during a hard frost: Mild, dry days in March or early April are better, as cut surfaces heal more quickly.
• Use sharp, clean secateurs: Crushed shoots weaken the plant and provide an entry point for fungi.
• Look carefully first: The vital buds are often inconspicuously positioned directly below the dried flower head.
• It is better to remove too little than too much: If in doubt, leave a shoot in place and observe how the plant responds.

Many gardeners report noticeably more flowers even in the first year after taking a gentler approach. The plants often do not look dramatically different, but the number of buds increases clearly.

Risks, special cases and useful additions

There are, of course, exceptions. Very old, severely overgrown hydrangeas that have produced hardly any flowers for years can sometimes benefit from more radical pruning. However, this often means accepting a whole year with fewer flowers while new flowering shoots develop.

Late frosts can also cause problems. In exposed locations, gardeners sometimes deliberately leave dried flower heads in place for longer, as they protect the buds like small umbrellas. Pruning is then best delayed until late March or early April, when the risk has reduced.

To complete the care routine, pay attention to two further factors: sufficient watering during dry spells and slightly acidic to neutral soil. Mophead hydrangeas in particular benefit from low-lime water, so in some areas it is worthwhile collecting rainwater for plants in pots and containers.

The difference between an “all right” hydrangea shrub and a truly impressive one does not ultimately come down to specialist fertiliser or exotic varieties, but small routines: gentle pruning in March, a healthy helping of mulch in winter, and a watchful eye on buds and shoots. Anyone who takes these habits on board can come remarkably close to the picture-perfect hydrangea in their own garden.