Hydrangeas: Monty Don’s crucial March task

Many hydrangeas prove disappointing despite costly compost.

One unobtrusive task in March determines whether the shrub bursts into bloom in summer or lets you down.

Hydrangeas and the overlooked March task

On television gardening programmes, it all appears effortless: a few cuts, some mulch, and timid shrubs soon become dense balls of flowers. In real gardens, the outcome is often quite different. Hydrangeas in particular cause plenty of frustration for amateur gardeners across German-speaking countries. British gardening expert Monty Don explains that the problem is usually neither fertiliser nor a “green thumb”, but a March routine that is almost always missed.

Why March decides hydrangea hopes

Although hydrangeas seem hardy, they are unforgiving when pruning is mistimed. The widely grown mophead hydrangeas (Hydrangea macrophylla), including ball and lacecap varieties, produce their flower buds on what is known as “old wood”. In other words, the shoots intended to flower in summer had already formed their buds during the previous year.

Pruning old wood at the right time

Cutting these stems back too early unknowingly removes the entire set of developing flowers. The plant will then put on fresh, green growth but produce scarcely any blooms - a familiar sight in many front gardens.

The crucial point is not how much is cut, but where and when