Harvest asparagus spears when 13-18cm (5-7in) tall cutting 2.5cm (1in) below soil level. Protect emerging spears from late frost with fleece.

To delay flowering, promote compact growth and control legginess of perennials such as  Anthemis, Echinacea, Helenium, Phlox, Sedum and Veronicastrum reduce growth by up to a half (‘Chelsea chop’).

Watch out for viburnum beetle larvae that can cause a severe damage to foliage of evergreen and deciduous Viburnum species.

Sow pumpkins, courgettes, squashes and outdoor cucumbers under cover or outdoors towards the end of month.

Trim back box (Buxus) topiary and hedges to encourage bushy growth. Old, damaged or neglected box usually responds well to hard pruning to within 15-30cm (6-12in) of the ground