When to plant rosemaryin Perth.

Growing rosemary in Perth: the specifics

Perth has a classic Mediterranean climate, hot, dry summers and mild, wet winters, giving it a completely different growing rhythm to the east coast. The long, dry summer (November-April) demands water-wise gardening and heat-hardy varieties, while the cooler months from May to October are Perth's prime growing season. Perth's warm winters mean brassicas, leafy greens, and tomatoes can all produce through the cooler months without frost damage. For rosemary, the productive window in Perth is year-round. Within that window, Rosemary is best established from semi-hardwood cuttings rather than seed, cuttings root easily and produce a plant true to variety, whereas seed-grown rosemary is variable. Take 10-15cm cuttings from new growth in autumn or spring, strip the lower leaves, and insert into a free-draining propagating mix. Roots develop within 4-8 weeks. In raised beds, rosemary is best positioned as a permanent resident at one end of a long bed, its woody shrub habit and perennial nature means it will be there for years, and planning around it from the start avoids disruption. Rosemary demands free-draining soil above all else, it will rot in heavy, wet, or poorly drained conditions. The free-draining nature of raised beds makes them ideal for rosemary, especially in high-rainfall areas. Never overwater rosemary or allow it to sit in water. Once established, rosemary requires almost no care, a hard prune after flowering in spring to maintain shape and encourage fresh growth is the primary management task. Do not feed heavily; rich soil produces lush but less aromatic growth. Choose varieties for purpose: 'Prostrate Rosemary' is low-growing and cascades beautifully over bed edges; 'Tuscan Blue' and 'Miss Jessop's Upright' are tall and upright with excellent flavour; 'Blue Lagoon' is compact and suited to smaller beds.

Sizing it for your household

1 plant is more than sufficient for a family of 4; rosemary is rarely needed in large quantities Ongoing; an established rosemary bush can produce kilograms of fresh herb per year. Plant Planner does this maths automatically once you tell it your household size, it’s the part most planners get wrong because they assume every household is the same.

The 60 cm spacing (with 80 cm between rows) means a standard 1.2 m × 2.4 m raised bed in Perth can hold 6 rosemary plants at maximum density, though in practice you’ll want to mix companions in, so plan for roughly 60-70% of that.

Companion plants for Perth

Good companions for rosemary include Broccoli, Cabbage, Kale, Beans. In Perth’s mediterranean/temperate climate, these pairings reduce pest pressure and improve pollination. Keep rosemary away from Cucumber, Pumpkin, they fight for the same nutrients or attract shared pests.

Perth-specific tips

• Perth's dry summers require drip irrigation or soaker hoses rather than overhead watering, conserve water and reduce fungal disease risk simultaneously.
• Unlike east coast cities, Perth's best tomato planting window is actually August-October for a summer harvest, with a second planting possible in late February.
• Perth's Mediterranean summers are too hot and dry for most leafy greens, focus on heat-tolerant herbs (rosemary, thyme, oregano) and water-efficient crops like sweet potato in summer.

Common problems

Phytophthora root rot is the most serious problem, caused by waterlogged soil. Ensure excellent drainage, especially in clay-based gardens. Rosemary beetle is a minor pest that can defoliate plants, handpick adults and larvae. Powdery mildew occasionally affects plants in humid, shaded positions, increase sun exposure and improve airflow. Spittlebug (froghoppers) creates frothy masses on stems; wash off with water.

Harvest

Harvest rosemary by snipping green stem tips 10-15cm long. The woody stems below do not regrow well when cut, always harvest green, current-season growth. Rosemary can be harvested year-round in most Australian climates. For large harvests, prune up to one-third of the plant after flowering in spring.