This is a method of pruning to limit the size of certain herbaceous perennials that is usually carried out around the time of the RHS Chelsea Flower Show in May. It stops plants from becoming too tall and leggy and then flopping, keeping them compact with a more bushy growth. Suitable plants for the "chop" are Asters, Campanula, Phlox and Sedum.
Prune Spring-flowering shrubs immediately after they have flowered to encourage better blooms next year. Typical examples include Forsythia, Ornamental currants (Ribes) and Flowering quince (Chaenomeles).
Although most of the woodland flowers will have finished flowering, now as the leaf canopy is rapidly closing over, there may still be the chance of seeing a favourite native flower, the Bluebell (Hyacinthoides non-scripta) that is usually found in ancient woodland but also grows in hedgerows and grassland.
Hawthorn (Crataegus monogyna), is a small tree that is traditionally found growing in hedgerows and is usually in flower this month, hence its other common name; "May". It produces highly-scented, creamy-white flowers that attract a wide variety of insects.
A familiar sight along roadside verges this month is Cow Parsley (Anthriscus sylvestris) with its clusters of white flowers that can be hard to tell from other Umbellifers. Other common names include; "Queen Anne’s lace" and "Mother-die", that suggests that your mother could die if the flowers were picked and taken indoors.