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May gardening tips

A garden in autumn colours

May’s gardening essentials

  1. Tip 1 Early flowering deciduous shrubs such as Forsythias, Weigela, and Spiraea should be pruned back when they have finished blooming.
  2. Tip 2 Cut back a third of the oldest canes to ground level, then cut back one third of the remaining branches by one third of their height.
  3. Tip 3 Remove the wilting seed heads from Rhododendrons and Azaleas, so that the plants energy can go to foliage growth and next year’s flowers, rather than seeds.
  4. Tip 4 Work lime in the soil around your Hydrangeas to produce pink flowers or Aluminium Sulphate for blue.
  5. Tip 5 Remove any sucker growths from fruit trees as soon as they appear.
  6. Tip 6 Keep a vigilant eye on the roses. Keep them sprayed for aphids and other pests and diseases such as black spot .
  7. Tip 7 Pines and other conifers can be kept to a compact size by pinching off the new growth 'candles'.
  8. Tip 8 Lilacs should be pruned lightly after they finish blooming, removing sucker growths and dead blooms. Feed lilacs in May with a good all purpose fertilisers after they have finished blooming. If your soil has an acidic pH, work a little lime into the soil as well.
  9. Tip 9 Dahlias, Gladiolas, tuberous Begonias, Lilies and Cannas and other summer flowering bulbs can be planted this month. Gladiolas bulbs may be planted at 2-week increments until the first of July to provide you with cut flowers until the first frost.
  10. Tip 10 Break off wilting Tulip or Daffodil heads but continue to feed and care for the plants until the foliage has died back naturally.
  11. Tip 11 Old plantings of Daffodils may be divided and moved when they have finished blooming, but treat them as growing plants and use care to protect the foliage and roots. Water them thoroughly after transplanting.
  12. Tip 12 It is best not to dig or move other spring flowering bulbs until their foliage has ripened and died back.
  13. Tip 13 Setting the stakes next to your taller flowers early in the season, will help to support the plant against winds as well as making it easier to 'train'.
  14. Tip 14 Promptly remove spent flowers from any plant unless your intent is to harvest the seeds.
  15. Tip 15 Carrots, lettuce, potatoes, corn, beans, peas and most popular vegetables (with the exception of the warmer weather crops) can be seeded or planted into the vegetable garden.
  16. Tip 16 Wait until mid to late May before planting the warmer weather crops like tomatoes, squash, cucumber, pumpkins and peppers.
  17. Tip 17 With a little luck, you may begin to see the first fruit on your strawberries by late this month. The birds will enjoy them very much if you don't provide some protective netting over them.
  18. Tip 18 Newly planted strawberries should have the blossoms picked off until they become well established.
  19. Tip 19 May is a good month to repair your lawn. Fill in the bare spots by slightly loosening surface of the soil and sow a good quality lawn seed over the area evenly.
  20. Tip 20 This is the time to eliminate lawn weeds by hand pulling, or the application of a 'weed and feed' fertiliser before they go to seed!
  21. Tip 21 Setting your mower for a higher cut during the spring months will help the grass to grow in fuller and help choke out the weeds.
  22. Tip 22 Check to see if your houseplants are root-bound. Water them thoroughly and carefully remove them from their pots. If the roots have compacted around the outside of the root ball, it is time to re-pot.
  23. Tip 23 Slugs and snails are out in full force right now. Make sure you take steps to control them now, before they have a chance to reproduce and devastate your garden.
  24. Tip 24 Frequent turning of your compost will turn your garden waste into flower food much faster.

Week-by-week gardening tips for May

Week 1

  • Sow fast-maturing and late flowering annuals directly into their flowering positions.
  • Move over wintered hardy annuals to their flowering positions.
  • Regularly water and feed greenhouse plants.
  • Feed seedlings and young plants which are growing poorly or have pale, yellowing foliage.
  • Remove faded flowers from daffodils, hyacinths and tulips.
  • Stake border plants to provide support as they grow.

Week 2

  • Take cuttings from summer flowering clematis.
  • Plant out annual climbers.
  • Begin feeding plants in containers and continue through the summer.
  • Harden off hanging baskets and window boxes ready to put in position outdoors when all danger of frost is over.
  • Plant both dormant dahlia tubers and young plants.

Week 3

  • Make sure fruit trees and bushes have sufficient water while the fruit is setting otherwise fruitlets are often shed.
  • Cover the grown under strawberries with straw or matting to protect the ripening fruit from mud and from slugs and other pests.
  • Feed newly shooting hardy fuchsias with a nitrogenous fertiliser and keep the base free from weeds.
  • Organise shading for the greenhouse using blinds, shading nets or shading wash.

Week 4

  • Plant out hardened off annuals when all danger of frost is over.
  • Sow French and runner beans and erect supports for climbing beans.
  • Start to cut lawns with naturalised bulbs: make the first cut high.
  • Harden off aubergines, courgettes, marrows, peppers, pumpkins and tomatoes grown from seed before planting outside.
  • Prune deciduous spring-flowering shrubs over three years old as they finish flowering.