A well-shaped hedge is one of the most effective things you can do for the overall look of a property — and one of the most damaging things when done at the wrong time. Perth’s climate has specific windows for each hedge species, and working against them causes brown-out, dieback, and slow recovery.
Here’s what you need to know for the most common Perth hedging species.
Lilly Pilly (Syzygium species)
Lilly pillies are Perth’s most popular screening hedge. They’re fast-growing, respond well to trimming, and maintain dense foliage year-round.
When to trim: Lilly pillies can be trimmed almost year-round, but the best windows are October–November (after the main spring flush) and again February–March (after summer growth slows). Avoid heavy trimming in June–July when plants are at their slowest growth rate.
How often: Two to three times per year maintains a clean formal line. Once per year is the minimum for a tidy appearance.
Technique: Always use sharp blades. Dull blades bruise stems and cause browning along cut edges. For a formal hedge, use string lines to keep the top level. Remove no more than 30% of foliage in a single session.
Common mistake: Trimming too hard in summer — cutting back to bare wood in 35°C heat causes serious dieback. Always leave a layer of green foliage on the exterior.
Murraya (Orange Jessamine)
Murraya is a softer, fragrant hedge that flowers twice a year in Perth — typically late September to October and again in late summer.
When to trim: Trim after each flowering period — around late October or early November after the spring flush, and again in early April after summer flowering. Trimming during flowering removes the blossoms and reduces fragrance.
How often: Two times per year, aligned with flowering cycles. Murraya grows more slowly than lilly pilly, so over-trimming creates sparse patches.
Technique: Light shaping rather than hard cutting. Murraya doesn’t regenerate from bare wood as readily as lilly pilly — always leave green foliage when cutting.
Photinia (Red Robin)
Photinia is valued for its dramatic red new growth, which appears after each trimming.
When to trim: Best trimmed in September (late winter/early spring), which triggers a flush of red growth through October. Can also be trimmed lightly in January–February. Avoid trimming from May to August — cold, wet conditions after trimming increases fungal susceptibility.
How often: Two times per year. Over-trimming repeatedly throughout the year weakens the plant’s ability to produce the red flush that makes it attractive.
Technique: Photinia tolerates hard trimming well. Cut back to the desired shape in spring and allow the red flush to emerge naturally. Never trim wet foliage — fungal disease spreads rapidly through cut tissue in moist conditions.
Westringia (Coastal Rosemary)
Westringia is a tough, drought-tolerant native hedge well-suited to Perth’s dry climate and sandy soils.
When to trim: Westringia can be trimmed almost any time, but avoid trimming in December to February during peak heat. The best windows are September–October and March–April.
How often: Two to three times per year for formal shapes. Westringia responds well to regular light trimming and develops denser foliage with consistent maintenance.
Technique: Westringia is forgiving and tolerates hard cuts back into old wood, though it recovers more slowly from extreme cutting. A light-to-moderate trim produces better results than infrequent heavy cutting.
Box (Buxus)
Box hedges are less common in Perth than on the east coast due to box blight susceptibility in humid conditions, but they’re used in formal garden settings in drier Perth suburbs.
When to trim: Early September and again in late November–December. Avoid trimming in summer — box stress in heat combined with cut wounds creates entry points for disease.
How often: Two times per year is usually sufficient. Box grows slowly, so over-trimming is rarely an issue.
Technique: Use clean, sterilised blades — blight spreads on cutting tools. If you notice brown patches or white fungal growth at the base of stems, do not trim further and treat with a registered fungicide.
Formal vs Informal Hedges
Formal hedges (flat tops, vertical sides, geometric shapes) require more frequent trimming — typically 3–4 times per year — and benefit from string lines and spirit levels to maintain precision.
Informal hedges (allowed to grow into their natural form) need only light tipping 1–2 times per year to maintain density without imposing a rigid shape. These are lower maintenance and more drought-resilient.
Tools That Make the Difference
Sharp, clean blades are non-negotiable. Hedge trimmers and secateurs should be sharpened annually at minimum and wiped down with a disinfectant between species to prevent disease spread. For precision on formal hedges, electric or battery-powered trimmers outperform petrol on fine detailing.
West Coast Greenscapes provides professional hedge trimming across Perth Metro. If your hedges need shaping, request a free quote or contact us to discuss your garden.