March and April are when I do most of my garden pruning in Melbourne, and it’s the time I get the most questions about what to cut and what to leave alone. The short answer is: autumn is great for pruning most established plants, but there are important exceptions.

The basic logic is simple. Pruning stimulates new growth. You want that new growth to happen when conditions are mild—not in the middle of a heatwave and not right before frost. Autumn gives plants time to recover and push out new growth while temperatures are still warm enough for active growing, but not so hot that the plant is already stressed.

What to Prune in Autumn

Summer-flowering shrubs that have finished blooming are prime candidates. Plants like crepe myrtle, hibiscus, and buddleia can be shaped and reduced now. They flower on new wood, so pruning now encourages the growth that will carry next summer’s flowers.

Hedges benefit from a final trim in late March or early April. This gives them clean lines heading into winter and enough time for a flush of growth to fill in before cold weather slows everything down.

Fruit trees that are deciduous get their major prune later in winter when fully dormant, but you can do light tidying now—removing water shoots, crossed branches, and dead wood. Don’t do heavy structural pruning on deciduous fruit trees until the leaves have dropped completely.

Perennials that have finished their summer display can be cut back. Salvias, geraniums, and similar plants that look tired and leggy now respond well to a hard cut. They’ll push fresh growth from the base that looks much better through winter.

Roses are a special case. In most of Australia, major rose pruning happens in mid to late winter—June or July depending on your region. But you can deadhead and lightly shape roses now. Remove spent flowers, any obviously dead or diseased canes, and crossing branches. Save the hard prune for winter.

What NOT to Prune in Autumn

This is where people make expensive mistakes.

Spring-flowering plants should not be pruned now. If a plant flowers in spring—camellias, azaleas, wisteria, lilac—it has already set its flower buds for next season. Pruning now removes those buds and you’ll get no flowers in spring.

The rule is straightforward: prune spring-flowering plants after they finish flowering, which means late spring or early summer. If you missed that window, leave them alone until they flower next year and then prune.

Native plants require careful consideration. Many Australian natives don’t respond well to heavy pruning, particularly into old wood. Grevilleas, for example, can be lightly shaped after flowering but cutting back into bare wood often kills the branch. Banksias are similar—prune only lightly, removing spent flower spikes and shaping tips.

Some natives prune beautifully. Westringias can be hedged hard and recover readily. Lilly pillies respond well to pruning almost any time. Know your specific plant before reaching for the secateurs.

Frost-tender plants in areas that get frost shouldn’t be pruned in autumn. Pruning encourages new soft growth, and soft growth is the most vulnerable to frost damage. If you’re in a frost-prone area, defer pruning frost-tender species until after the last frost in spring.

In Melbourne’s inner suburbs, frost is rarely an issue. But in the outer east or Dandenong Ranges, late frosts can damage freshly pruned plants. Check your local frost date data from BOM if you’re unsure.

How to Prune Properly

Technique matters as much as timing.

Cut at an angle about 5-10mm above an outward-facing bud. The angle should slope away from the bud so water runs off rather than sitting on the cut. This reduces disease entry.

Use sharp tools. Dull secateurs crush stems rather than cutting cleanly. Crushed wounds take longer to heal and invite infection. I sharpen mine at the start of each pruning season and clean them between different plants with a spray of methylated spirits.

Don’t remove more than one-third of a plant’s total growth in a single pruning session. Taking more than that stresses the plant and can trigger excessive weak regrowth or die-back. If a plant is severely overgrown, spread the renovation over two or three seasons.

Step back regularly. It’s easy to get focused on one section and over-prune it. Step back every few minutes to look at the overall shape. Aim for a natural form that’s slightly smaller than you ultimately want—it’ll grow.

The Clean-Up Matters

Don’t leave pruning waste sitting on garden beds. Diseased material should go in the bin, not the compost. Healthy prunings can be mulched through a chipper or composted in a hot compost system.

Branches left on the ground create habitat for slugs and provide pathways for fungal diseases to spread. Clear up as you go.

Tools for the Job

For stems up to about 15mm diameter: bypass secateurs. Get the best pair you can afford—they’ll last years with proper maintenance. Felco secateurs are the standard recommendation for good reason.

For branches 15-30mm: loppers give you better reach and more leverage. Again, bypass style rather than anvil for live wood.

For anything larger: a pruning saw. Don’t try to force loppers through thick branches—you’ll damage the plant and possibly yourself.

Autumn pruning is one of those garden tasks that’s genuinely satisfying. You can see the immediate results, and you know you’re setting your garden up for a strong spring. Just remember: if it flowers in spring, put the secateurs down.

— Nina