Gardening Jobs for May

Here are a few ideas of what you could be doing in the garden this month

YouGarden’s Top Tip

Get climbing

Secure any wayward stems of clematisroses, honeysuckle, or any other climbing plants that you have in your garden. This will prevent them from snapping in any strong winds and depriving you of a vertical show of summer blooms.

Prune early flowering clematis as the blooms fade. If your climbers have outgrown their space, keep them within their bounds by pruning the stems above the leaf joint.

Fill your garden with scent this summer by planting sweet pea seedlings in a sunny spot against a trellis or other supports. If you forgot to sow seeds earlier this year, buy some ready-grown plants.


Hanging Baskets

  • If you haven’t already prepared your hanging basket displays and stored them away in your greenhouse, then now is the time to plant them up with garden ready plants or plugs you’ve grown on yourself – and we have all the plants that you need for the job!
  • Fill your basket ¾ of the way with some Premium Professional Compost then make little wells in the soil where you want to plant your plugs. Place the rootballs into the wells, then add a few scoops of Swell Gel & Feed containing water-absorbing cyrstals and slow-release fertiliser, before covering the top of the rootball with compost and secure in with your fingers.
  • Water in well, then hang!

Beds and borders

  • Tidy up any worn-out hellebores. Cut off flowering stems of stinking hellebore at ground level, and dead head the many varieties of Lenten rose (Helleborus x hybridus).
  • Many perennials will flop by mid-summer, so make your plants sturdier by giving them the ‘Chelsea Chop’ – this is a technique carried out by nurserymen at the end of May. Plants, such as Rudbeckia, Helenium, Sedum and Solidago, can be cut back by half, this will result in bushier plants that will flower slightly later.
  • If you have been extra cautious with your exotic and tender plants, now is the time to remove their frost protection. Bananas, tree ferns and palms are now actively growing, and fleece or other insulating material will hamper the new growth.
  • Prevent the spent flower heads of lupins, delphiniums and other early flowering perennials turning to seed by cutting them back to a set of leaves with secateurs. Apart from leaving tidier.
  • Thin out crowded delphiniums, leaving 5-7 shoots on established plants to improve final flowers.

Plants in pots

  • Pull up any forget-me-nots, wallflowers, violas, and other spring bedding plants as their flowers fade. Chop them up and add to compost heaps.
  • Water your plants well in the morning so they have a good supply that will last all day – avoid watering during the day as splashes on foliage could become scorched in the sun.
  • Mulch the surface of pots with gravel, grit, crushed glass or another decorative material to reduce moisture loss and prevent any weeds from growing.
  • Move pot-bound shrubs or perennials into larger containers, this will ensure they grow healthily. Generally, plants will need re-potting annually, but you can check this by lifting them out of their container – if all you can see is a mass of roots, they will be in need a new pot.

Trees and shrubs

  • Overgrown or untidy evergreen shrubs? Restore their shape by pruning out any offending branches. Cutting in late spring give plants plenty of time to produce new growth that will ripen before cool weather sets in later in the year.
  • For a great display of flower next year, dead head lilacs when the flowers fade. To do this, wait until you see two shoots beneath the spent bloom start to swell, then snip off the flower head just above them with secateurs.
  • Lightly prune ribes, pieris and kerria when the flowers fade – cut back lanky shoots and remove any diseased growth.

In the kitchen garden

  • Sow sweetcorn seeds in pairs, place them 2.5cm deep and 45cm apart. Water them well and after germination, thin each pair to leave the strongest seedling.
  • Earth up potatoes once stems are about 22cm tall, this will prevent developing spuds turning green. Draw up soil, leaving 10cm of growth showing.
  • Sow seeds of French beans, cabbage, runner beans, kale, carrots, and cauliflowers outside. For summer salads, try radish, salad leaves and spring onions.
  • Pinch out tops of broad beans to prevent an infestation of black bean aphid, which is attracted to tender young shoot tips.
  • Feed tomato plants weekly with a fertiliser high in potash to help the fruit swell. Tie in stems and remove side-shoots, as necessary.
  • Remove the central flower spike from clumps of rhubarb to ensure the plant continues to produce stems for harvesting.
  • Tidy up rows of raspberry canes by pulling up shoots that are too far away to be tied in easily.
  • Remove every other fruit on gooseberry plants to ensure those that remain have plenty of space to swell up.
  • Keep a close eye out for caterpillar-like, sawfly larvae on gooseberries and currants. Causing rapid and severe defoliation of plants, they can be controlled by spraying with pesticides containing pyrethrum.
  • Make sure you are keeping your young fruit trees well-watered, as this is when they will really start to grow.