April shower bring May flowers. Love this saying except when it continues to rain in May and all spring.
Here are things you can do in your garden or should do this May.
• Thin out drifts of hardy annuals.
• If potted Harden* off half-hardy plants by leaving them outside during the day and bringing back under cover at night for 7 to 10 days before planting outdoors.
• Harden off dahlias and tender exotics such as Canna for planting as soon as the risk of frost has passed.
• You can still divide herbaceous perennials now to improve their vigour and create new plants.
• Divide Hostas as they come into growth.
• Trim back spreading plants such as aubrieta, alyssum and candytuft after they have flowered to encourage fresh new growth and more flowers.
• Don't be tempted to cut down or tie up the foliage of spring-flowering bulbs, let them die down naturally.
• To reduce the spread of forget-me-not, lift the plants now to prevent heavy self-seeding. Pictured.
• Prune your Penstemons now - cut all the old shoots back to the base provided there is new growth at the bottom of the plant. If there are no new shoots at the base, cut just above the lowest set of leaves.
• Take cuttings of tender perennials such as Fuchsia, Argyranthemum and Pelargoniums (geraniums). The new shoots of hardy perennials can also be used for cuttings.
• Take softwood cuttings of shrubby herbs (such as sage and lemon verbena)
• Prune out overcrowded and dead stems of early-flowering clematis (C. alpina, C. cirrhosa, C. macropetala, C. armandii and their cultivars) after flowering.
• Tie in climbing and rambling roses. Laying the stems horizontally will help to produce more flowers.
• Tie in your sweet peas with plant support rings to encourage them to climb.
• Prune spring-flowering shrubs after flowering.
• Cut back flowered shoots of Choisya to promote a second flush of flowers in autumn.
• Trim lavender plants now, cutting off any old flower heads and about 2.5cm (1 inch) of the current year's growth.
• Feed and water container plants.
• Top-dress permanent pot plants to refresh the compost.
• Give your container plants a balanced liquid feed every two to four weeks to promote healthy growth.
• Plant up pots and baskets of summer bedding and harden off before placing in position. In cold areas wait until June.
• Start to closely inspect your plants for pests and diseases - early prevention is easier than curing an infestation.
• Pick off larvae of rosemary, viburnum and lily beetles as soon as they are seen.
• Look out for signs of blackspot on roses. If discovered, Blackspot can be treated with a systemic fungicide.
• Continue to weed beds and borders to prevent competition for water and nutrients.
Harden, this means that you will have to gradually acclimatize them to outdoors over a period of time, which will result in a hardier plant. Start by putting plants out during daytime hours and bringing them back indoors in the evening