May 2018 Garden Tips

Garden tips for May


As the weather starts to improve, your plants should flourish!

Cut back tender shrubs and sub-shrubs such as Penstemon, Caryopteris and Fuchsia after the danger of frost has passed.

Clip evergreen hedges. If not too woody, shredded clippings can be added to the compost heap.

Prune spring-flowering shrubs such as japonica or Japanese quince (Chaenomeles), Choisya and Ribes after flowering.  Evergreens such as Viburnum Tinus can also still be trimmed this month.

Twining climbers (such as honeysuckle and Clematis) need regular tying in and twining around their supports.

Check roses for signs of black spot, aphids and leaf-rolling sawfly damage.

Inspect box and holly trees for signs of blight.

Ensure newly planted trees and shrubs do not dry out. Water with rainwater or recycled water wherever possible.

Divide Primula (primroses) after flowering, planting them in a nursery bed until they are ready for planting out again in the autumn, for a display the following spring.

Divide hostas as they come into growth.

Protect lilies, delphiniums, hostas and other new shoots from slugs and snails.

Inspect lilies for red lily beetles.

Now is the ideal time to give Lavender plants a trim to encourage new growth.

Apply a liquid fertiliser to spring bulbs after they have flowered, to encourage good flowering next year, and help prevent daffodil blindness.

Let the foliage of spring-flowering bulbs die down naturally.  Once the leaves start to yellow they can be removed.

Now is a good time to sow a wildflower patch or meadow. Ensure that the seed mix you get is right for your soil and conditions – usually, they are mixtures of grasses and wildflowers.

If soil conditions are not too wet, dahlia tubers can be planted directly into the garden soil from early May onwards for late summer flowering. Gladioli can also be planted at this time directly outdoors for late flowering.

Prevent weed seedlings becoming established by hoeing borders once a week.

Harden off your half-hardy bedding plants by leaving them outside for the day and bringing them under cover at night.

Provided the weather is mild and the grass is growing, applications of lawn fertilisers and weed killers can be made to established lawns.

Mow lawns when necessary – whenever the grass is growing – the aim is to maintain a constant height throughout the year.

Ensure new lawns (either from turf or seed) do not dry out during dry spells. Keep off them for as long as possible to allow establishment.

Provided the weather is mild and the grass is growing, applications of lawn fertilisers and weed killers can be made to established lawns.

In the greenhouse remember to tie in the leading shoots of indoor crops such as tomatoes, peppers and aubergines as they grow. Stems are much less likely to break or grow in undesired directions if they’re trained from early on.

Train the new stems of passionflowers and other glasshouse climbers over frames or on horizontal wires.

Regularly inspect plants, and also the structures of the greenhouse and conservatory, for glasshouse red spider mite, whitefly, thrips and other pests. Control with approved treatments, and hang yellow sticky traps to help monitor numbers of flying pests.

Brush up fallen compost and debris in the greenhouse and pick off dead leaves from plants. This will help prevent pests and disease spreading.

Are you growing strawberries? To keep the fruit clean and make sure no mould grows, lay straw between the strawberry plants. And, keep all your other fruit that’s growing well watered in dry spells.

If you’re thinking of growing some vegetables this year then now is the time to start. Marrow, courgette and sweetcorn are all ready to be sown in the greenhouse. Not forgetting brussel sprouts, kale, peas and swede – either keep them in the greenhouse or keep them covered outside. And, as soon as your potatoes breakthrough, earth them up.

Sow French beans in individual pots for planting out next month.

Thin out any vegetable seeds sown directly into the garden to the recommended spacing’s. Water the rows well afterwards to settle the soil around the seedlings.

Planting sunflowers is one of the easiest ways to provide food for birds and are useful plants to have in a wildlife-friendly garden. Bees, and sometimes butterflies, love the nectar and feed on the flowers when they’re in full bloom. Then greenfinches and goldfinches will munch on the nodding, drying seed heads.

Clean and top up birdbaths regularly, especially in warm dry weather. Keeping a birdbath clean helps to prevent birds catching diseases.