Monty Don’s March Hydrangea Pruning and Mulch Trick for More Flowers

Many gardeners feed and water faithfully, yet still wonder why their hydrangeas flower less lavishly with every passing year. British television gardener Monty Don relies on a simple March routine: highly selective pruning followed by a layer of mulch. It may sound unremarkable, but it changes how the shrub copes with frost, moisture and buds-and, in turn, how many flowers it produces.

Why March determines hydrangea flowers

Hydrangeas have a reputation for being easy-going, resilient plants, capable of thriving even in partially shaded spots where roses would long since have given up. Yet many varieties are extremely sensitive to being pruned at the wrong time.

This is particularly true of traditional bigleaf hydrangeas (Hydrangea macrophylla), often called mophead hydrangeas, which flower on what is known as “old wood”. In other words, the buds for the following summer have already formed on the stems in the previous year and remain there throughout winter.

Gardeners who tidy up in winter by cutting away all the old flower heads can easily remove the buds intended for the entire next season. The shrub may look neat and orderly in May, but appear surprisingly sparse by July.

“The crucial point with hydrangeas is rarely how much you cut-it is when and where you put the secateurs.”

Monty Don, along with fellow British gardener Alan Titchmarsh, therefore advises a change in mindset: accept the plant’s winter dormancy, leave faded flower heads in place, and wait until March before reaching for the secateurs. By then, most hard frosts should have passed and the buds will be clearly visible.

Monty Don’s hydrangea pruning trick: gentle deadheading, not hard cutting back

Many gardeners treat cutting back and removing spent blooms as if they were the same task. With hydrangeas, understanding the difference can mean either abundant flowers or a leafy green mound.

How to prune in March, step by step

For mophead hydrangeas, Monty Don recommends only a light intervention in March. This is not a drastic makeover, but careful work just above the right pairs of buds:

• Wait for a frost-free spell in late February or March, ideally when the buds are visibly swelling.
• Inspect each dried flower head individually and cut only just above the highest healthy pair of buds.
• Remove blackened, dead or brittle stems completely at their base.
• Leave strong green stems untouched, as these will carry the season’s flowers.

This method, known as deadheading, removes only the dried bloom and often the frost-damaged tip of the stem. The two buds beneath remain intact and can reliably grow away in spring.

“For hydrangeas in March, the secateurs should protect the buds, not ‘shape’ the plant-Monty Don reserves shaping work for after flowering.”

When more substantial pruning is suitable

Not every hydrangea responds in the same way. Some types, including many panicle hydrangeas and smooth hydrangeas (Hydrangea paniculata and Hydrangea arborescens), flower on “new wood”, meaning growth made in the current year. These cope better with harder pruning in late winter or very early spring.

Hydrangea type	Flowers on	Recommended pruning	Timing
Mophead hydrangea (macrophylla, mophead)	Old wood	Remove only old blooms just above the buds; thin out old stems after flowering	March (lightly), with heavier work immediately after flowering
Panicle hydrangea (paniculata)	Current-year wood	Cut back firmly while retaining the plant’s structure	Late winter to very early spring
Smooth hydrangea (arborescens)	Current-year wood	Prune back boldly, usually cutting it down substantially	Late winter to March

The straightforward rule of thumb for home gardeners is this: if you do not know which hydrangea you have, take the cautious approach and treat it like a mophead. It is better to prune a little less in the first year and see how it flowers.

The mulch that quietly improves the soil

Alongside pruning, Monty Don consistently uses mulch around hydrangeas, roses and other shrubs during winter. It may not look especially significant, but it has a major influence on how evenly a plant grows and how well its buds survive the winter.

What Monty Don recommends for mulching

He uses well-rotted organic material. Suitable options include:

• Mature homemade garden compost
• Mushroom compost
• Bark mulch or chipped bark, preferably slightly acidic material such as pine bark

The mulch layer should be around 5–10 cm deep. Apply it on mild days in January or in very early spring, provided the soil is neither frozen nor completely waterlogged.

“Monty Don prefers a thick layer of mulch every other year to a thin covering every year-the effect on soil life and the root environment is much greater this way.”

The key detail is that mulch should form a ring around the plant rather than touch its stems. Leave a clear gap around the crown so that the base does not rot and mould problems do not develop.

Why mulch encourages more hydrangea flowers

A mulch layer shields the soil from sudden changes in temperature. This reduces frost damage around the roots, while the faded flower heads offer the above-ground buds a little additional protection. Mulch also helps the soil retain moisture for longer and gradually feeds soil life with nutrients over several months.

Hydrangeas are especially sensitive to fluctuating moisture levels. Prolonged dryness or standing water causes stress, and the plant is then more likely to focus on survival than producing plentiful flower buds. Mulch acts as a buffer against both extremes.

Mistakes many home gardeners repeat every year

In typical suburban gardens, the same habits repeatedly cost hydrangeas their flowers:

• Drastic pruning in December: In the urge to tidy up, every old flower head and stem is cut back hard. The buds for summer end up with the garden waste.
• Fresh bark mulch against the stem: Unrotted material temporarily draws nitrogen from the soil and can cause the base of the plant to rot.
• Waterlogging in containers: Attractive patio pots without drainage holes may look good, but they can cause hydrangea roots to rot.
• Overdoing general fertiliser in spring: The plant produces lush green growth but forms fewer buds because it remains too strongly in growth mode.

Correcting just one of these problems and trying Monty Don’s March pruning approach often brings a noticeable improvement in both the number and size of flower heads in the very first summer.

Practical scenario: a 30-minute spring check

For many home gardeners, the diary is already full. A low-maintenance sequence makes this routine easier to keep. Here is an example of a quick hydrangea check on a mild March morning:

1. Check the forecast. If a frost-free week is expected, get started.
2. Roughly clear weeds from around each hydrangea and gently loosen the soil.
3. Hold each stem carrying a faded flower head, locate a healthy pair of buds and cut just above it.
4. Take out dead stems, stems growing inwards and any that cross over one another.
5. If it has not already been done, spread a 5–10 cm layer of mulch around the shrub without covering the stem.

Nothing more needs to be done at this stage. Watering can wait until later, drier periods, while fertiliser can be added in April or May using a slow-release organic feed.

What terms such as “old wood” and “bud protection” actually mean

Many guides use technical terms that sound as though they belong in a textbook. There is nothing mysterious about “old wood”: it simply means stems that have already completed one season and become woody. On many hydrangeas, these are precisely the stems that hold the flower buds for the following year.

In this context, “bud protection” works on two levels. First, the faded flower heads physically shelter the buds like small umbrellas. Secondly, careful pruning and stable soil conditions protect buds from frost, drying out and weakening through lack of nutrients.

Why patience pays off with hydrangeas

Anyone who has once pruned their hydrangeas too severely will often face an almost flowerless summer. That can be frustrating and quickly lead to hasty remedies, such as adding more fertiliser or cutting back again. A better approach is to think over a period of two or three years.

In the first year, it is worth using gentle March pruning focused on protecting the buds, together with a good layer of mulch. In the second year, you can be more selective: after flowering, remove one or two of the oldest, tired stems close to ground level so that vigorous young shoots can emerge from below. This gradually rejuvenates the shrub without sacrificing an entire flowering season.

Gardeners who establish this combination of patience, a small March task and calm, protected soil for their hydrangeas often have an eye-opening moment: the shrub looks almost unremarkable in spring, then suddenly bursts into large flower heads in high summer, as if someone had secretly buried an XXL fertiliser treatment. In reality, it is simply a well-timed trick that surprisingly many gardeners overlook.