Your May gardening to-do list

The days are getting warmer and it’s time to tidy up spring plants and get ready for the summer. Here are our top 10 jobs for you to do now:

  1. Stake tall herbaceous perennials such as delphiniums, and peonies now before they start flopping over other plants.
  2. Deadhead spring bulbs but resist the temptation to cut back foliage, let it die back naturally.  It’s a good idea to grow tulips in containers that can be moved out of sight when they’ve finished flowering.
  3. Keep pyracantha trained against a wall by removing shoots growing directly into or away from the wall.  Shorten the others to about 8cm to encourage short spurs, which bear buds and then showy autumn berries.
  4. Prune spring flowering shrubs like Spirea ‘Arguta’ and Kerria japonica, taking flowering stems back to buds lower down the plant and cut back flowered shoots of choisya for a second flush.  The vigorous Clematis montana can also be pruned back now.
  5. Water new plants in warm dry periods, in particular young vegetables, developing fruits and newly planted perennials, trees and shrubs that are getting established.  Planting with organic matter will help retain moisture as will mulching.
  6. Tie in sweet peas regularly, encouraging them to climb vertically up supports.  Vigorous climbers such as clematis and roses also need their shoots tied in to control where they grow.
  7. Lightly trim formal evergreen hedging such as box with hand shears, which don’t bruise like mechanical hedge trimmers.
  8. Keep checking roses for aphids spraying them off with soapy water or squashing them off with your fingers.
  9. Protect strawberries with straw (to control weeds and lift berries off the ground) and net to keep the birds off.
  10. Sow annuals such as cornflowers and veg such as French beans and courgettes under glass, planting out when the chance of frost has passed, while you can direct sow hardier veg such as beetroot and broccoli.  Plant out dahlias and tender exotics such as canna toward the end of the month.