The gardening jobs to tackle now for a thriving summer garden

May is an exciting time in the garden, as flowers suddenly surge in height and spring flowers such as lilacs, irises and peonies fill the garden with colour. To be out in the garden is delightful and there are some rewarding things that will get your patch ready for summer. Many perennials soar – though that puts them in danger of being beaten down by summer squalls. Resurrecting the fallen mess is rather disheartening, so stake them as soon as feasible. While metal supports are durable and quick to insert, sticks and string must often be used. Be generous with the sticks, buying in canes if necessary. Shorts Lofty top-heavy plants such as delphiniums might need a cane per shoot. This can turn into a bit of a barricade, so consider thinning the shoots by half – you will get better flowers, too, on the remaining stems. The “Chelsea chop” also helps with taller plants. Shorten stems by up to half with shears or secateurs, so that the plants are less tall when they reach flowering, and need less staking while flowering is delayed, often with more, if somewhat smaller flowers. Typically aim to chop about half a clump or half of the clumps to spread the flowering period by several weeks. The more you cut off, the more flowering is delayed. Typical candidates are Anthemis (cota), Echinacea purpurea, Eupatorium, Helenium, perennial Helianthus, Hylotelephium (Sedum), Phlox paniculata, Rudbeckia, Symphyotrichum (aster) and Solidago. Ladybird enjoy snacking on aphids so are good friends to have in the garden (Photo: RHS/Georgi Mabee) Keep the hoe moving to catch weeds while small – it is astounding how fast they can grow as the weather warms and the soil remains moist, setting seeds in just six weeks. Chop off perennial weeds such as ground elder and bindweed to keep them weak, so they can be more easily winkled out in autumn, when the flowers won’t be spoiled by the unavoidable disruption. Thwart perennial weed clumps such as couch grass by covering with cardboard held down with some mulch, perhaps hosting a container where watering is convenient. The now-cleaned ground can be planted in autumn. Aphids – blackfly or greenfly, multiply amazingly – each female carries a daughter ready-formed inside and that daughter has her own offspring within, ready to be launched on to tender, protein-rich new shoots. Being defenceless, they are soon devoured by the larvae of hoverflies, lacewings and ladybirds. Adult ladybirds do good work, too. The speed of aphid demise is a marvel to see. In almost all cases, aphids will be sufficiently knocked back to cause only modest, acceptable damage and loss of crop. Where some intervention is needed – to save a broad bean crop, for example – apply a material that works by physical effect such as SB Plant Invigorator, which leaves no residues. Remember that aphids are at the bottom of the garden ecology food chain and plentiful aphids eventually feed through via bigger insects and spiders to birds, bats, frogs, hedgehogs and other garden wildlife. Summer stretches out before us and plants sown in May or June will have three months of good growing conditions to be ready for winter. Biennial flowers including Canterbury bells, foxgloves, hollyhocks, lupins and sweet Williams are classic choices best sown in a spare space in the veg plot. Wallflowers and pansies tend to go to seed if sown very early, so leave these until after mid-June. Thin, water and feed these plants ready to set out in their final positions in September, to flower in 2027.Finally, bear in mind that the season is running a little earlier than usual, so June tasks may well fall due in May.The RHS is a charity inspiring everyone to grow via its research, advisory, outreach, shows and gardens. For more information, visit: rhs.org.uk