Photinia includes several dozen species of evergreen shrub commonly used as a hedge. These shrubs are extremely tolerant of a wide range of soil conditions, which is why they are such popular landscape plants. Photinia can grow up to 12 inches per year to a height of 12 to 15 feet. Several varieties of photinia are suitable for the home garden, but one of the most impressive is 'Red Robin' or red tip photinia. It produces bright-red new growth in the spring and responds well to shearing several times a year to spur colourful new growth. Photinia may be trimmed year-round, but pruning is best done from late February through March.
Prepare your pruning tools by sharpening them. Hold the blade portion of the implement at a 45-degree angle and drag it lightly over the sharpening stone. Repeat this motion three or four time but no more. Any more times and you are sharpening the blade and then making it dull again. If the blade won't sharpen, it is time to replace it.
Remove any dead or broken wood from the photinia. Cut dead wood back to a live branch. Make cuts at a 45-degree angle and cut 1/4 inch above the next piece of wood. When removing a large branch, cut back to the main wood or trunk but not into the branch collar. The branch collar is the swelling in the wood out of which the branch grew. Cutting into this can damage the shrub and invite disease.
Prune photinia once annually so that you do not have to do as much shaping. Photinia doesn't need much pruning except for cosmetic purposes. Never remove more than one-third of the wood at one time. Cut back to growing points. These can be recognised by following the terminal growth back to where the stem branches out. Cut on the outside edge of the growing point at an angle 1/4 inch away from where it branches out.
Shear or trim as needed to keep the photinia hedge looking its best. Hand shearing is best, if more time consuming, because you won't be left with ragged, chopped leaves. A gas or electric trimmer makes short work of trimming the hedge. Go straight across the top and the exposed sides for a boxy look or start at the bottom and stroke up and over for a more natural, rounded look. Keep the bottom of the hedge just slightly wider than the top for strength and so that sunlight can penetrate all the way down.
Start training photinia during its first year of growth. Dock the top to promote bushing and trim small amounts over the first couple of years to keep the growth habit down. Rake up debris and loose leaves every time you cut the shrub to minimise hiding places for pests and prevent disease spread.
Consistent trimming of red tip photinia throughout the year will keep it producing attractive foliage but may expose the shrub to fungal disease in humid or wet temperate regions like the Pacific Northwest. The more hygenic method is to trim in late winter when the plant is dormant. Photinia is subject to numerous fungal diseases.