May

In The Flower Garden This May

Plant summer hanging baskets, adding good-quality compost, slow-release fertiliser and water-retaining crystals, to keep them in top condition. Protect them from late frost under cover.

Harden off half-hardy plants by leaving them outside during the day and bringing them back under cover at night for 7 to 10 days before planting outdoors.

Continue dividing herbaceous border perennials to improve vigour and create new plants.

Thin out drifts of hardy annuals.

You’ve still got time to plant any container-grown evergreen climing shrubs now the risk of frost has passed.

Trim lavender plants, cutting off old flower heads and about 1.5cm (1 inch) of the current year’s growth.

Tie in sweet pea plants with sweet pea support rings to encourage them to climb.

Trim back spreading plants such as aubrieta, alyssum and candytuft after they’ve flowered, to encourage fresh new growth and more blooms.

Start planting out summer bedding plants towards the end of this month in warmer parts.

Top Tip:

Look after your finished spring bulbs for next year. Once they’ve gone over, resist the temptation to cut back the foliage. Instead, let it die and break down on its own and add liquid fertiliser all around the clumps. This will give you an even better display next Spring.

This Month's Key Tips
  • Mow lawns weekly.
  • Plant out summer bedding towards the end of the month, when the weather gets warmer.
  • Open greenhouse vents and doors on warm days.
  • Watch out for late frosts. Tender plants will need protecting.
  • Water early and late to get the most out of your water, recycle water when possible.
  • Check for nesting birds before clipping hedges.