Autumn in the Garden: What to Do in May

As the crisp air of May settles across South Australia, gardeners enter one of the most important transitional periods of the year. With summer heat behind us and winter on the horizon, the soil still holds enough warmth to support strong root development. This makes May a prime month for planting, preparing, and maintaining your garden for a fruitful winter and vibrant spring.

Planting in May: Edibles & Ornamentals

May is an excellent time to get planting. The cooler weather and moist soil create ideal conditions for both edible crops and ornamental plants to establish strong root systems before winter sets in.

Vegetables to Plant Now

• Broad beans, garlic, onions, shallots, and leafy greens like spinach and silverbeet thrive when sown in May.
• Peas and snow peas also perform well in cool conditions and can be trained up trellises or garden frames for a productive winter harvest.

Herbs That Love the Cold

• Parsley, coriander, chives, and thyme grow especially well in the cooler months, adding both beauty and flavour to the garden.

Add Winter Colour

For a splash of colour through winter and into early spring, plant flowering annuals such as:

• Pansies, violas, snapdragons, calendula, and primulas.

Planting Natives and Perennials

May is also an ideal time to establish native shrubs and perennials. The milder conditions reduce transplant shock and promote healthy root development. Consider natives like:

• Grevilleas, banksias, and kangaroo paw, which will flourish once warmer weather returns.

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Pruning and General Maintenance

As the growing season slows, May becomes a time to tidy and care for your garden’s structure.

• Deciduous trees and shrubs can be pruned once their leaves have fallen.
• Avoid cutting spring-flowering plants now, as their buds are already forming for next season.
• Trim back summer perennials that have finished blooming to tidy up beds and encourage healthy regrowth.

Collect fallen leaves and either compost them or use them as a natural mulch around trees and garden beds.

Dividing and Replanting Perennials

Dividing established perennials revitalises plants and offers more to share or spread throughout the garden. Ideal plants to divide include:

• Agapanthus, daylilies, irises, and ornamental grasses.

Carefully lift the plant, divide it into smaller clumps, replant into refreshed beds, water well, and mulch to protect the roots.

Mulching and Fertilising

Mulch for Winter Protection

Top up mulch now to:

• Insulate soil
• Suppress weeds
• Retain moisture

Use organic mulches like pea straw, sugarcane, or bark chips, which break down to improve soil structure.

Feeding Your Garden

While heavy feeding isn’t necessary, citrus trees and winter crops benefit from a light application of slow-release, balanced fertiliser to support steady growth through winter.

Lawn Care in Autumn

Though lawn growth slows, some attention now will set the stage for spring:

• Rake fallen leaves to prevent fungal issues.
• Aerate compacted areas to improve oxygen flow to roots.
• Apply a seaweed tonic or mild lawn conditioner for health without overstimulating growth.

Managing Common Pests

Even in cooler months, some garden pests remain active:

• Aphids may appear on new growth—treat with a strong water spray or natural insecticidal soap.
• Snails and slugs thrive in damp weather and can be managed with bait or homemade traps.
• Caterpillars feeding on winter crops can be handpicked or treated with organic solutions like Bacillus thuringiensis (Bt).

Caring for Indoor and Potted Plants

Indoor plants and pots need seasonal adjustments too:

• Move sensitive pots to sheltered spots to protect them from the cold.
• Reduce watering as growth slows and evaporation decreases.
• Wipe down leaves and check for pests like scale or fungus gnats to keep plants healthy.

Preparing for Winter Crops

Clear out old summer crops and refresh garden beds with compost or well-aged manure.

• Practice crop rotation to prevent soil-borne diseases.
• Sow green manure crops like oats or vetch in fallow beds to improve fertility and structure for spring.

Final Thoughts

May is a month of quiet productivity and thoughtful preparation. It’s a time to plant for the future, clean up the past, and ensure your garden is healthy and ready for winter. The work you do now—whether growing food, cultivating flowers, or caring for your lawn—will reward you in the seasons ahead.

Happy gardening!

Ask one of our knowledgeable garden staff members for advice if you have any questions regarding anything having to do with your garden, indoors or out. We would be pleased to lead you on the correct path. Call us on 1300 699 185 or visit your local store.