Relax in your little oasis of calm!
Here are your July gardening jobs with added links if I have more information on the subject. Some of the jobs are relevant if you’ve fallen behind or if the weather’s been bad. See my garden in pictures in July.
Week 1
Autumn-flowering bulbs, such as autumn crocuses, Colchicum, Sternbergia, Amaryllis, and Nerine, can be planted now.
Take cuttings of patio and container plants ready for next year.
Prop up tall perennials such as lupins, delphiniums, and gladioli.
Liquid feed container plants and keep them well watered in dry spells.
Powdery mildew can play havoc with plants such as clematis, roses, and honeysuckle. It can also cause yellow and distorted leaves on cherry laurel (Prunus laurocerasus).
Watch out for aphids (greenfly and blackfly) on stems and leaves of young shoots.
Capsid bugs eat small holes and tears in the new foliage of ornamentals such as Caryopteris, Fuchsia and Dahlias.
Look out for tall, flowering stalks on established bamboo and remove them promptly. Flowering can weaken the plants, as well as being unsightly.
Ensure newly planted trees and shrubs do not dry out. They need much more water than people imagine.
You may notice damage to the leaves of Viburnum by viburnum beetles. The damage is not usually bad enough to call for treatment.
Damp down greenhouses on hot days.
Remove dead foliage and blooms from water lilies and other aquatic plants. Cut back any marginal plants that are getting out of hand. Continue to skim blanket and floating weeds.
Top up ponds and water features if necessary. A spray attachment on the hose will aerate the water. Any pumps on water features should be left on during sultry nights, as oxygen levels are lower in such conditions.
July gardening jobs – Week 2
Some seeds are best planted just after collection, and others may need special conditions to break dormancy (e.g. some alpines). If unsure, sow seeds in ‘batches’, i.e. one immediately after collecting, one in winter, and one in the following spring.
Deadhead flower borders regularly to prolong flowering. Disbud and dead-head dahlias if growing for large blooms. Leave roses that produce attractive hips.
Mulching borders can help retain moisture and keep down the weeds. A thick layer of mulch (5-7.5cm/2-3in all over) works best.
Look out for and treat black spot on roses and scab on Pyracantha.
Inspect lilies for red lily beetle, whose larvae can strip plants in days. Vine weevils can also be a problem at this time of year.
Clip fast-growing hedges such as Leyland cypress throughout the growing season, but avoid birds’ nests.
Neat circular areas removed from the edges of roses and other leaves are telltale signs of leaf-cutter bees. These fascinating creatures are best tolerated since damage is rarely severe.
Week 3
Cut back delphiniums and geraniums after the first flush of flowers to encourage a second flowering period. Feed after cutting them back.
Divide clumps of bearded iris.
Most perennial weeds are best dealt with now. Digging out often works.
Propagate pinks and carnations (Dianthus) by layering or by cutting, improving the look of untidy clumps.
The sudden collapse of apparently healthy clematis, especially the large-flowered cultivars, could indicate clematis wilt.
Prune June-flowering shrubs such as Philadelphus and Weigela after flowering. Prune deciduous magnolias if necessary.
Cover ponds with nets or safety grilles in gardens where young children play. These also stop leaves from falling in. Clean out debris to improve water quality and prevent excess growth of weeds and algae.
Thickened and curled margins on bay trees (Laurus nobilis) are a sign of damage by the bay sucker. Scale insects can also affect the bay at this time of year.
One of the most important and recurrent July gardening jobs is keeping track of conservatory and greenhouse pests. Check plants regularly for signs of whitefly, leafhopper, glasshouse red spider mite, mealybugs and scale insects. Yellow card sticky traps are a low-cost tool for monitoring numbers and types of flying pests. If large numbers of a pest are found, apply organic treatment.
Tie in climbing roses and ramblers as they grow. Remove rose suckers and tree suckers.
July gardening jobs – Week 4
Cutting back plants in baskets followed by feeding can encourage new growth and help revive tired displays.
Plants with a carpet-like growth habit, e.g. some alpines, can become patchy, with central areas dying off. These patches can be filled with gritty compost to encourage re-growth.
Start collecting seeds from plants you want to grow next year, especially hardy annuals such as Calendula, poppy, and love-in-a-mist.
Take semi-ripe cuttings of shrubs such as Choisya, Hydrangea, and Philadelphus. Root them in pots of gritty compost in a cold frame or even with a plastic bag tied over them.
Propagate by taking internodal cuttings (taking stem sections above and below a leaf, not immediately below a leaf joint).
Some late-flowering border perennials need a quick-acting feed before they come into bloom, especially if the soil is not fertile.
Brown patches on conifers may show an earlier infestation by cypress aphids. Telltale signs include black sooty mould along the stems and shed skin cases. Once the damage is done, conifers take a long time to recover. Where hedges are affected, prune out brown shoots and tie in neighbouring branches to help fill the gaps.
Cuttings can be taken and grown on in the greenhouse. Fuchsias and Pelargoniums (geraniums) are good candidates.
To catch up with June’s gardening jobs, visit my week-by-week guide.
