With all the freshness of spring and the promise of summer to come, many gardeners regard May as one of the best months in the garden. Make the most of the warmer weather to start getting ready for the summer months. Just taking a leisurely stroll through a garden can lift the spirits. It’s a great time of year to visit some of the many gardens that will be opening up to the public to glean ideas and inspiration.

Continue to deadhead spring-flowering bulbs that have gone over; this allows the bulb to store up more energy to produce flowers next year. You must leave the foliage intact for at least 6 weeks after flowering, but simply snap off the flower heads with your fingers or a pair of secateurs. Use a general organic fertiliser around the base of the bulbs to encourage the development of new flowers next year.

Lightly trim formal evergreen hedges, such as box, even if it hasn’t grown very much yet. Box doesn’t take kindly to being cut back hard, so the sooner it’s trimmed the better it keeps its shape. Although it takes more time, this job is best done with hand shears, as opposed to a mechanical cutter, for a better finish. In recent years, box hedging and topiary in our gardens have been suffering a two-pronged attack. The first invasion comes from the ‘box tree caterpillar’, which is the larvae of a moth that feeds on box (Buxus) plants. The caterpillars produce a significant web over the plant, which may also show patches of dieback, especially apparent on trimmed plants.

A second problem is a fungal disease known as ‘box blight’, resulting in bare patches and die-back, especially in topiary and parterres. Box blight is unfortunately hard to manage. Typically, the leaves turn brown and fall, leading to bare, brown, unsightly patches. If your box is affected, you may want to consider an alternative such as Japanese holly (Ilex crenata.)

Box blight photo copyright m.borden, Creative Commons Attribution-Share Alike 2.0 license.

Prune spring-flowering shrubs once they have finished flowering. Examples are things like kerria japonica, forsythia, and spirea. Also, if you have one, prune the glorious clematis Montana after it has flowered. This beauty is a very fast-growing climber that can easily get out of hand unless pruned hard every year. It’s a good choice of plant if you have an ugly wall or fence that you want to cover quickly. Finish planting new shrubs if you possibly can this month before it gets too dry.