Most garden advice arrives as separate pieces: one article on soil, another on pests, another on design. What is missing is the order. A new garden bed succeeds or fails on a sequence of decisions made in a particular order, and the most expensive mistakes are the ones made early, before a single plant is bought. This guide runs the sequence end to end for Australian conditions, from working out what your site actually offers through to getting plants through their first summer.
Quick facts
| Climate zone | Example cities | Best planting window | Window to avoid |
|---|---|---|---|
| Tropical | Darwin, Cairns | April to August, in the dry | December to March, the wet |
| Subtropical | Brisbane, Coffs Harbour | February to April, and August to October | December to January |
| Warm temperate | Sydney, Perth | March to May, and September to November | January heatwaves |
| Cool temperate | Melbourne, Adelaide | March to May, and September to November | Midwinter waterlogging |
| Cool and highland | Canberra, Hobart, Armidale | September to November, after last frost | May to August frosts |
| Arid and semi-arid | Alice Springs, Mildura | March to May | November to February |
Choosing the right site and plants
Spend an ordinary day watching the space before you buy anything. Note when direct sun arrives and when it leaves. Six hours or more is full sun, three to six is part shade, and under three is shade, and almost every plant label in the country uses those categories. Watch where water sits after heavy rain, because a spot that puddles for more than a few hours after a storm has a drainage problem that will kill most plants regardless of what else you do.
Then work out what soil you have. Squeeze a handful of moist soil: if it holds a ribbon when pressed between finger and thumb it is clay-dominant, if it falls apart it is sandy, and something in between is a loam. Our guide to soil types explained covers how to identify and work with each. Only once you know aspect, drainage and soil type is it worth choosing plants, and steps to plan your garden covers the layout decisions that follow.
How to plant
Prepare the whole bed, not individual holes. Clear existing weeds completely, including roots, then cultivate to a spade's depth across the area. Spread 50 to 100 millimetres of compost over the surface and work it through the top 200 millimetres. In heavy clay, gypsum applied at label rates helps flocculate the soil over a season. The detail is in how to prepare the soil for planting.
Set every plant out on the surface, still in its pot, before you dig anything. Space by mature width, not by the size of the plant in front of you: small shrubs at 600 to 800 millimetre centres, medium shrubs at 1 to 1.5 metres, large shrubs at 1.5 to 2 metres, and small trees at 3 to 5 metres from any structure. Stand back and adjust before committing.
Dig each hole twice the width of the root ball and exactly its depth. Loosen the sides with a fork so roots can leave the hole. Tease out any roots circling the outside of the root ball, or the plant will strangle itself over several years. Position the plant so the top of the root ball is flush with the surrounding soil, or 20 to 30 millimetres proud in heavy clay. Backfill with the excavated soil, firm gently, and form a shallow saucer of soil around the plant to hold water.
Water in immediately and thoroughly, enough to fully wet the root ball and the soil around it, which is usually five to ten litres for a shrub. Then mulch to 75 millimetres, keeping the mulch a hand's width clear of every stem.
Ongoing care
Watering
The first summer decides everything. Water deeply twice a week for the first eight weeks, then weekly for the rest of the first year, adjusting for rain. Deep infrequent watering drives roots down; light daily watering keeps them at the surface where they cook in a heatwave. Check by pushing a finger or a screwdriver into the soil beside the root ball rather than judging from the surface. Watering 101 covers technique in more depth.
Feeding
Do not fertilise at planting beyond what the compost provides; new roots are easily burnt. Wait six to eight weeks, then apply a controlled-release fertiliser at label rate. After that, one application in early spring suits most beds, with a second in midsummer for hungry plants such as citrus and roses. Use a low-phosphorus native formulation on grevilleas, banksias and hakeas.
Pruning
Leave new plants alone in their first season apart from removing damaged growth. From the second year, tip-prune shrubs after flowering to build density, and remove crossing or inward-growing branches on trees while they are small enough to cut with secateurs.
Common problems and fixes
Plants that sit still for months without dying are usually planted too deep or into a hole that acts as a sump in clay. Lift and replant with the root ball flush or slightly proud. Wilting despite wet soil is the same problem: roots suffocating rather than drying out.
Yellowing new growth points to nutrient deficiency or high pH, while yellowing old leaves is more often nitrogen. Weeds returning quickly usually means the mulch layer is thinner than 50 millimetres. Chewed leaves, sticky residue and distorted new growth all have specific causes, and identifying and treating common plant pests and diseases works through the diagnosis.
Frequently asked questions
When is the best time to plant in Australia?
Autumn in most of the country, because soil is still warm while the air has cooled, which favours root growth over top growth. In the tropics plant in the dry season from April to August; in cool and highland districts wait until after the last frost in spring.
How deep should I dig a planting hole?
Exactly as deep as the root ball and twice as wide. Digging deeper than the root ball causes the plant to settle and end up too low, which is one of the most common causes of slow decline.
How far apart should I space plants in a new bed?
By mature width, not current size. Small shrubs at 600 to 800 millimetres, medium shrubs at 1 to 1.5 metres, large shrubs at 1.5 to 2 metres. Beds always look sparse for the first two years, and planting closer to fix that creates a decade of pruning.
Should I add fertiliser to the planting hole?
No. Concentrated fertiliser against new roots burns them. Improve the whole bed with compost before planting and apply a controlled-release fertiliser six to eight weeks later.
How long does a new garden bed take to fill in?
Two growing seasons for groundcovers and small shrubs, three to four for medium shrubs, and five or more for trees. Mulch generously in the meantime rather than over-planting.
Ready to plant?
Get the soil right first and the rest follows. Our potting mixes, mulches and fertilisers range covers everything needed for bed preparation, and the garden makeover essentials collection is a good place to start choosing plants once the bed is ready.
