What to do in the garden in May

Fill your hanging baskets with petunias in May.
Image: Supachita Krerkkaiwan

May is the start of the transition from spring to summer, so make sure you’ve got a good gardening routine down and start cutting back on those spring flowers and plants.

Plants and Flowers

Give your Lavender a trim to encourage further growth.
Image: Marut Homtawee
  • Harden off your half-hardy bedding plants by leaving them outside for the day and bringing them under cover at night. Do this for 7-10 days before planting out into beds, containers and hanging baskets.
  • Prune your Penstemons now by cutting back to the lowest pair of leaves. Give your Penstemon a feed with a slow-release fertiliser to help boost new growth and flowers this summer.
  • Prune winter and spring-flowering Clematis such as ‘Winter Beauty’ and Clematis armandii now if they’re out-growing their supports.
  • Now is the ideal time to give Lavender plants a trim to encourage bushiness. Clip about 2.5cm (1 inch) off the current year’s growth.
  • Start to feed your container plants with a balanced fertiliser and continue every two to four weeks throughout the summer. Alternatively use a slow-release fertiliser.
  • Don’t be tempted to cut down or tie up the leaves of your spring bulbs to tidy them up. The plants need the leaves to feed themselves for next year! Once the leaves start to yellow they can be removed.

Fruit and Veg

Keep your potatoes healthy by earthing up the soil.
Image: Irene_A
  • Put netting around your strawberry plants, raspberry canes and other soft fruit bushes to prevent birds from eating your crop.
  • Earth up your potatoes now. If you’re using potato grow bags just top up the bag with more compost. To find out more about earthing up and growing potatoes in general, read our ‘How to grow potatoes’ article.
  • Thin out any hardy annuals or vegetable seeds sown directly into the garden to the recommended spacings. Water the rows well afterwards to settle the soil around the seedlings.

Trees, Shrubs and Grasses

It’s time to prune your spring-flowering shrubs, like this stunning Forsythia.
Image: taylon
  • Prune spring-flowering shrubs such as Honeysuckle ‘Winter Beauty‘ and Forsythia after flowering has finished.
  • Give your evergreen hedges a trim now whilst they are in active growth. Box, Privet and Yew can be trimmed twice each year during the growing season.
  • Keep any new fruit trees well watered in hot weather. Remove any blossom or fruits during the first year to focus the plant’s energy on growing roots

Do you have any further jobs you like to complete in May? Let us know in the comments below, or share them with us over on our Facebook page.

Van Meuwen

Author: Van Meuwen

Horticultural mail order specialists. Working hard to bring you the best quality well-established plants as well as exciting new varieties.

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