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Gardening in September

Spring is in the air …

It’s that wonderful time of year when the garden comes to life again after Winter. Deciduous blossom and fruit trees are in full bloom, there are bulb and seasonal flowers aplenty and other trees and shrubs are sprouting bright green new leaves and shoots.

Watering can, gumboots and plants on the side of a walkway


All this garden action can be a little mis-leading because cold days and frosts are still likely for a few more weeks. There’s plenty for you to do in the garden this month, mostly tidying up and preparing for planting next month. Start your disease control program on deciduous fruit trees this month.

What to plant now: 

In cold and cool temperate regions, it is still a little too early to plant evergreen trees or shrubs including citrus. Wait until all danger of frost has passed. Strawberry runners and artichoke suckers can be planted and an early sowing seeds of late spring/early summer vegetables may be made into seed trays under cover or indoors.

In warm temperate and subtropical areas, Australian native plants, evergreen trees, shrubs and climbers can continue to be planted, as well as salad vegetables, herbs and seasonal flowering annuals. Check out what’s in stock in your garden centre.

Garden full of pink and white flowers


  • Seasonal flowers:

Bloomer pots of spring flowering annuals can still be planted out this month for patches of instant impact colour – pansies, violas, Iceland poppies, cinerarias, calendulas are just a few. In warm areas plant seedlings of bedding begonias, marigolds, impatiens and nasturtiums.

  • Woody and perennial herbs:

“Hard” herbs - rosemary, sage, thyme, bay laurel, oregano, mint* – may be planted now in warm climates. “Soft” herbs – parsley, basil, coriander, chives, tarragon – may be grown indoors in cooler areas or outdoors in warmer climates.

*Mint should be grown in a pot to stop it becoming invasive.

  • Spring & summer vegetables: 

Keep planting beetroot, brassicas, peas, rhubarb crowns and artichoke suckers in warmer areas. Salad greens (lettuce, rocket) and Asian greens can also be sown. In the cooler south, plant rhubarb and asparagus crowns and strawberries. 

The Vegetable Patch:

Harvest now:

The last of the winter veggies, including cabbage, kale, cauliflower, Brussels sprouts and broccoli should be harvested early in the month. New season’s asparagus will be peaking now. Harvest spears when about 15cm tall. 

What to plant now:

Continue planting certified virus-free strawberry plants and runners. Rhubarb crowns should be planted as soon as possible. It’s too cold in southern areas to sow tomato seeds, even under cover. Wait until early October. 

In cooler areas seeds or seedlings of the following may go into sunny, well prepared beds: 
  • Broad bean
  • Carrot
  • Celery
  • French bean
  • Lettuce
  • Leek
  • Onion
  • Parsnip
  • Dwarf pea
  • Climbing pea
  • Potato tubers
  • Silver beet
  • Sweet corn 

Person planting a seed
In temperate to warm areas plant:
  • Beetroot
  • Carrot
  • Chinese cabbage
  • Choko
  • Kohl rabi
  • Tomato
  • Pumpkin
  • Zucchini
Veggie patch tips for September:
  • Water in newly planted seedlings with a liquid fertiliser for vegetables and herbs such as Osmocote Boost+Feed Vegetables, Tomatoes & Herbs or a certified organic fertiliser to give them a good start.
  • After sowing seeds, water well to moisten the soil, then wait until shoots appear before watering again. 
  • Hand pull or hoe out weeds as they appear – they compete for nutrients and moisture and may also harbour pests that could attack your crops.
  • Pull out the last of the winter crops and put them into the compost bin if they are disease-free.
  • Preparation for spring sowing and planting should be well underway. Keep the soil tilled, weed-free and moist. 

Fruit & Flower Beds:

Fruits to harvest now:

Only the warmer parts of the country are likely to have any fruit to harvest this month. Mandarins, tangelos, grapefruit and lemons should be plentiful and, in tropical areas, mangoes and paw paws (papaya) will be starting to ripen.

Group of mangos on a table
What fruit to plant:

Evergreen fruiting plants such as passionfruit vines and citrus can planted in warm to tropical areas. In temperate to cool areas, wait until the danger of frosts has passed. Potted deciduous fruit trees and vines can be transplanted this month. It’s best to get them in and established before the weather gets too warm in late spring.

The range available may include:

  • Fig 
  • Apple
  • Pear
  • Cherry
  • Plum
  • Apricot
  • Plumcot
  • Nectarine
  • Peach
  • Persimmon
  • Almond
  • Walnut
  • Mulberry
  • Pomegranate
  • Quince
  • Raspberry
  • Blackberry
What flowers to plant:

Potted roses in full leaf can be planted now. It’s too late now to plant advanced flowering pots out into the garden but they can be used to add splashes of colour to verandas and decks. 

In cool areas, sow seeds into seed trays of:
  • Amaranthus
  • Bedding begonia
  • Candytuft
  • Carnation
  • Celosia
  • Eschscholtzia
  • Geum
  • Linaria
  • Lupin
  • Nasturtium
  • Petunia
  • Scabiosa
  • Sweet William
  • Verbena
  • Wallflower
  • Zinnia

Bright orange flower in the middle of the frame
In warmer areas, plant annual seedlings of:
  • Dianthus
  • Gaillardia
  • Geum
  • Gypsophila
  • Honesty
  • Impatiens
  • Nasturtium
  • Petunias
  • Statice
  • Zinnias 
Garden jobs for the month:
  • Keep flowering annuals and bulbs growing and flowering well with regular applications of Osmocote Boost+Feed All Plant Types.
  • Give all established trees, shrubs and perennials an application of a long-term Osmocote Controlled Release Fertiliser or an organic slow release fertiliser that’s suited to the type of plant – there’s an extensive range to choose from. Follow instructions for applications rates and methods.
  • Spring blossom trees may be pruned as soon as they finish flowering. Follow the same principles used for deciduous fruiting trees.
  • Apply a copper-based spray to deciduous fruit trees immediately after petal fall to combat fungal diseases like brown rot and freckle. Repeat every 10 – 14 days until trees are fully leafed.  
  • It’s peak flowering time for cool climate orchids like cymbidiums. Plants may be brought indoors so the beauty of their spikes of blooms may be admired, but don’t keep them inside for prolonged periods.
  • Some spring flowering bulbs may be past their best now but don’t cut the flowers or leaves off. Allow them to die down naturally. 

Purple flowers blossoming in front of a group of leaves


Indoor Plants:

  • Plants inside the home assist in purifying the air as well as lending a touch of greenery to your living areas. 
  • Natural light is important but don’t stand pots on north or west-facing windowsills where they will be exposed to direct sun through the glass.
  • Place a saucer or bowl of water near your plants to humidify the air or regularly mist them with a water atomiser.
  • Wipe leaves occasionally with a damp cloth to keep them clean.
  • Feed every few weeks with ready to use Osmocote Pour+Feed Indoor Plants – no mixing required.


Mid-September is the ideal time to sow a new lawn or lay instant turf. There’s just enough warmth in cool areas to encourage germination and/or good root growth so the new lawn will establish before it gets too hot. Prepare the area by removing all weeds, hoeing the soil to break up clumps and levelling it. Add a layer of Lawn Builder Topdress Mix and Lawn Builder Starter Slow Release Lawn Food as per bag instructions before sowing or laying turf.

Person holding seeds to fertilise the lawn


If you have not already fertilised the lawn this spring, you should do so now.

Pest Control:

Leave with a rough edge


  • Slugs and snails can be active whenever there are young plants around – Defender Snail & Slug Pellets in a bait trap will protect your plants and keep your pets safe.
  • Watch for aphids and other sap-sucking pests on the tender young shoots of roses and other trees and shrubs. Defender Pyrethrum Insect Spray will control them. Don’t forget to spray the undersides of leaves as well as the top surfaces.
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