Your May garden will burst with colour

May is the start of the summer and with it comes longer evenings and warmer weather. It seems every time you look at the garden, something new is in flower. Buds are bursting open to soak up the sun’s energy.

Prune spring-flowering shrubs such as ribes and forsythia now that they have finished flowering. Both are pruned in the same way. Start with a shoot that has dead flowers at its tip. 

Follow it back until you find a young side shoot that hasn’t flowered and cut the main stem just above it. Keep going until you have done the whole shoot.

Check climbers on trellises or walls. They will be making lots of new growth. Tie in the shoots you want to keep to extend the framework and cut out any that are growing away from it. Check all your variegated shrubs. Sometimes new growth on them may be green. 

This is the shrub reverting back to its original colour. If left, the shrub will soon be mostly green as the green shoots grow faster than the variegated ones. Simply pinch the shoots out at the bottom.

Tall and floppy perennials will need supporting. The trick is to put in the supports before they are needed. This means that the plant will grow and cover the support. Use supports that are one third to one half the eventual height of the plant.

Dig up and divide primroses and polyanthus when they have finished flowering. Simply pull the clumps apart with your hands and plant them. The mother plants have a short life span and division rejuvenates them. Plant sweet peas 15cm/6in apart at the foot of the trellis or netting. Tie in the first shoots after this they will do it themselves. Cut back aubrieta alyssum and arabis by simply trimming them with scissors after the flowers have gone over.

Shops are now, and have been for many weeks, selling summer bedding. By all means buy it and plant up your hanging baskets, tubs and window boxes. But do not put them out until June. There is still the possibility of frost. Any temperature under 3°C will kill summer bedding. If you can’t resist the temptation, plant them up and keep in a frost free glasshouse or poly tunnel. If you don’t have these you can put them out during the day, if it’s warm enough, and bring them in at night.

When planting up summer bedding, don’t penny pinch. They will flower from now until the first frost, which can be in November. That is amazing value. Empty out the containers completely. Fill with new (decent) potting compost. Fill the container with as many plants as you can fit into it without squashing the rootballs. The finished container should have a gap of 2.5cm/1in between the rim of it and the top of the compost to allow room for watering.