Trees and shrubs

Pruning and training

Prune June-flowering shrubs such as Philadelphus and Weigela after flowering. Prune deciduous magnolias if necessary.

Fast-growing hedges such as Leyland cypress should be clipped as necessary throughout the growing season.

Tie-in climbers and ramblers as they grow.

Propagation

Take semi-ripe cuttings of shrubs such as   Choisya  ,  Hydrangea  and Philadelphus. Root them  in pots of gritty co mpost in a cold frame or even with a plastic bag tied over them.

Clematis can be propagated by taking internodal cuttings (i.e. taking stem sections above and below a leaf, rather than cutting the stem immediately below a leaf joint).

Air-layering is another method of propagation that can be used for some climbers, such as  Akebia , and some shrubs, such as Magnolia. 

General maintenance

Look out for tall, flowering stalks on established bamboos 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 often need much more water than people imagine

Remove rose suckers and tree suckers.

Pest and disease watch

Brown patches on conifers may indicate an earlier infestation by the cypress aphids. Telltale signs include black sooty mould along the stems and shed skin cases. Spraying earlier in the summer may have helped, but once damage is done, conifers can take a long time to recover. Where hedges are affected prune out brown shoots and tie in neighbouring branches to help fill the gaps.

Thickened and curled margins on bay trees (Laurus nobilis) are a sign of damage by the bay sucker. Scale insects can also affect bays at this time of year.

Neat circular areas removed from the edges of rose and other leaves are telltale signs of leaf-cutter bees at work. These fascinating creatures are best tolerated since damage is rarely severe.

Yellow and distorted leaves on cherry laurel (Prunus laurocerasus) indicate a powdery mildew problem.

You may notice damage to leaves of Viburnum by viburnum beetles. The damage is not usually bad enough to warrant treatment.