Roses: When, How & What to Use for Blooms That Last

Roses are timeless garden favourites, but to truly thrive, they need the right feeding schedule. This guide covers everything you need to know about fertilising roses in Australia—from planting to flowering—including how often to feed, what products to use, and tips for climate-specific care in places like Adelaide and Melbourne.

Where to Plant Roses & Growing Basics

Sunlight: Roses need 5–6 hours of direct sun per day. Morning sun helps dry leaves and prevent fungal issues.
Soil: Choose rich, well-drained soil. If heavy or sandy, dig in compost or plant in a raised bed or large container.
Spacing: Allow air circulation between plants to prevent disease and promote even growth.

Roses are heavy feeders with deep roots. For best results, establish a regular feeding plan based on your location and rose type (hybrid tea, shrub, climbing, etc.).

How to Fertilise Roses (Step-by-Step)

Step 1: Water deeply before fertilising to prevent root burn.
Step 2: Apply fertiliser at the base, not on foliage.
Step 3: Water again after applying to activate nutrients.

Use liquid fertiliser for quick uptake during active growth and flowering. For consistent results, alternate between a balanced NPK and a bloom booster.

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When to Fertilise Roses in Australia

Spring (August–October): Begin feeding as new leaves and buds appear. This fuels strong, early growth.
Summer (November–January): Continue regular feeding every 2–3 weeks to maintain flowering.
Autumn (February–April): Feed lightly to support final blooms and strengthen roots before winter.
Winter (May–July): Pause feeding while plants are dormant. Prune in late July to early August and prepare to restart feeding.

Feeding Roses in Melbourne & Adelaide

In southern climates:

Start fertilising in **late August** after pruning.
Feed every 2–3 weeks from **September to April**.
Pause during **winter dormancy** (May–July).

For warm-temperate or subtropical zones (e.g. Brisbane, Perth), fertilising may continue longer into autumn depending on weather.

How Often to Fertilise Roses

In garden beds: Feed every 2–3 weeks during the growing season using full strength.
In pots: Feed every 2 weeks at half strength to avoid build-up in confined soil.

Always water after applying and avoid feeding during heatwaves or extreme cold snaps.

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What Is the Best Fertiliser for Roses?

Roses need high nitrogen early on, followed by phosphorus and potassium to support buds, blooms, and disease resistance. Calcium and magnesium prevent yellowing and flower drop.

NPK 20-20-20 – Balanced and versatile. Use after pruning and throughout early growth to build strong stems, lush foliage, and dense branching.
NPK 4-18-38 + Cal-Mag – Perfect for flower production. Boosts bloom size, colour intensity, and petal strength. Also helps prevent leaf yellowing and nutrient stress.

Signs Your Roses Need Fertiliser

Yellowing lower leaves
Small or pale blooms
Leggy growth with few buds
Black spots or poor recovery after pruning

These symptoms often appear mid-season and can be corrected with proper feeding.

The Complete Grow Rose Feeding Routine

NPK 20-20-20 – Use after pruning and during leafy growth (Aug–Oct).
NPK 4-18-38 + Cal-Mag – Switch when flowering starts (Nov–April) to improve blooms and reduce disease risk.

Explore the full Complete Grow fertiliser range to help your roses bloom bigger, brighter, and longer—all season long.