What to do in the garden in May

In the garden

May is the last comfortable month for working before summer. Get the garden ready for the heat. Cover the soil in beds and tree pits with 5-8 cm of mulch: bark, wood chip or gravel. The soil stays cool and moist for longer and fewer weeds come up.

Deadhead faded flowers and check roses for aphids, powdery mildew and rust.

Lawn

Mow often, but raise the cutting height to 5-7 cm on cool-season blends. Longer grass shades the soil and copes better with drought. Give it its last feed before summer.

Watering

Water early, between 6 and 9 in the morning, when evaporation is lowest. It’s better to water less often for longer than a little every day: the water soaks deeper and the roots grow down. After watering, check by hand that the soil is moist 10 cm down.

Pruning

• Hedges: a maintenance trim before the real heat.
• Spring-flowering shrubs, once they finish flowering.
• Tip back herbs such as rosemary and lavender when they finish flowering.

Vegetables and fruit trees

Water the vegetable patch regularly so the tomatoes don’t split. Put straw mulch between the plants. Sow green beans, sweetcorn, melons and watermelons. On citrus the fruit has set: keep watering steady and don’t let the tree go thirsty, or it will drop its young fruit.

Plants of the month

• Bougainvillea, plumbago and bignonia for pergolas and walls.
• Lantana, verbena and salvia for flowers all summer.
• Agapanthus and daylilies in partly shaded spots.

Hedra’s tip

Before June arrives, switch the timer to its summer schedule and check every zone with the system running. A blocked dripper goes unnoticed in May; in July it can dry out a shrub in a few days. Ten minutes of checking now saves plants.