It’s a lovely time of year at the moment, with warm, sunny days and cool, crisp evenings. It’s great gardening weather and the perfect opportunity to plant, fertilise and prepare for winter.

Skip to what to plant in the garden in May

Skip to which plants need feeding in May

Skip to which plants to prune in May

Skip to garden pests, diseases and weeds to look out for in May

Skip to May's general lawn and garden care tasks

Skip to your May garden centre shopping list


What's flowering in Sydney gardens in May?

Clockwise from left: Cyclamen, correa, azaleas, crowea and chrysanthemums are all showing their beautiful blooms this month.

What to plant in the garden in May

  • Right now, it’s all about being growing your own edibles where you can, whether from seed or seedling. May weather is perfect for planting asparagus, broad beans, broccoli, cabbage, potato, rhubarb, rocket, spring onions, strawberries and winter varieties of lettuce. All of these can be grown really easily in containers – you can even grow potatoes in a hessian sack! It’s also the time to pick up a mushroom kit.
  • Fill your garden with colour courtesy of ageratum, alyssum, aquilegia, calendula, Canterbury bells, cineraria, coleus, cornflower, delphinium, everlasting daisy, hollyhock, impatiens, larkspur, lobelia, pansy and primula.
  • It’s time to plant azalea, camellia, citrus, conifer and all deciduous trees, shrubs, climbers and roses.
  • May is your very last chance to plant spring-flowering bulbs. Don’t miss out on daffodils, hyacinth, lilium, lily-of-the-valley and tulips.
  • Cyclamen are looking their best in May. They make fantastic indoor plants and their delicate flowers can bloom for months!

Which plants to feed in May

  • A helping of liquid fertiliser for flowering annuals and veggies will give you splashes of colour and a healthy crop come winter. We recommend Amgrow Organix Harvest for the best results.

Which plants to prune in May

  • Cut wilted flowers off chrysanthemums and dianthus.
  • Trim lavender for spring flowering, ensuring you don’t cut into the hardwood.
  • Finish trimming hydrangea flower heads for a striking and long-lasting cut flower display. You should also prune your plant to a set of two plump buds, ready for the next flowering season. Again, don’t cut into the hardwood!

Garden pests, diseases and weeds to look out for in May

  • If you’ve planted brassicas, such as broccoli, cabbage, cauliflower, turnips or pak choy, you might notice cabbage white butterfly caterpillars leaving a trail of destruction. An application of Nature's Way Caterpillar Killer Dipel should solve the problem.
  • Keep snails and slugs away from bulbs, annuals and clivia with pellets like Multiguard Snail & Slug Killer (use as per packet instructions).
  • Check indoor plants for scale infestation and treat with PestOil.
  • Spray fruit trees such as apricot, plum, peach and nectarine for brown rot with lime sulphur. Remove diseased leaves and fallen fruit to prevent further spread.

May's the time to lift and divide strappy-leaved plants, spray for bindii, collect autumn leaves for composting and treat winter grass.

May's general lawn and garden care tasks

  • Get ahead of this year’s bindiis by spraying with Bin-Die.
  • Now’s the time to ward off nasty winter grass. This weed seeds in autumn, winter and spring, then dies off in summer heat. Left untreated, it’ll weaken your lawn and result in more winter grass next season. As soon as you notice winter grass, spray with a selective weed control like Amgrow Winter Grass Killer. For more advice on autumn lawn care, click here.
  • Lift dahlia tubers from the ground and store them in a dry position in a cool airy shed for replanting next season.
  • Treat the soil around your hydrangeas if you want to change their colour. Apply lime or Hydrangea Pinking Liquid for pink shades. For blue flowers, apply aluminium sulfate or Hydrangea Blueing Liquid. It's much too late to change flower colour when flowers start budding in December.
  • Collect fallen autumn leaves and add to your compost bin. They're a great source of nutrients for your garden!
  • Divide strappy-leaved plants such as agapanthus, clivia, liriope and iris that have started to bunch and look messy. It’s a great time to dig them up, divide them and replant in an orderly fashion.

Your May garden centre shopping list

  • Mushroom kit to enjoy your own home grown mushrooms.
  • Worm farm to convert food scraps into nutrient-rich worm castings, which produce a high-quality soil conditioner.