Plant selection for Perth

The short answer: build every Perth plant list in the same order. Start in the Waterwise Plant Directory, filter to readily available so you only specify what a nursery can actually supply, then check any tree against the shot-hole borer host list and any unfamiliar exotic against the Western Australian Organism List. That is three checks and about ten minutes, and it is the difference between a schedule that survives contact with a wholesaler and one that does not.

The three directories, and what each is for

Use	Tool	What it gives you
Shortlisting	Waterwise Plant Directory	Search by suburb or name; filter by availability, origin, garden type, colour, growth habit
Local provenance	Apace WA suburb selector	What grew on your soil before the subdivision — 17 Perth vegetation complexes
Horticultural detail	Kings Park grow-it-at-home	Mature size, aspect, drainage, planting season, pruning, per species

Greenlife Industry WA is the industry body behind the directory; its useful contribution to a plant list is the fifteen accredited Waterwise Garden Centre locations, where staff have been trained on the range rather than merely stocking it.

One honest limitation. Every plant in the directory is already classed as waterwise, so it will not rank plants by water need. Hydrozoning is still your job.

Hydrozones

Water Corporation’s five-step method makes step two grouping plants with similar water requirements together. The only published, verified Perth dataset that scores individual species on water need is the tree guide, which uses a three-point drop rating. Borrow it for the whole garden.

Zone	Water Corporation drop rating	Meaning	Where it goes
1 — dry	0	No supplementary watering once established	Verge, front garden, far boundary, hot west walls
2 — low	1	Once a week once established	Main beds, screening, most of the garden
3 — regular	2	Twice a week once established	Entry, courtyard, outdoor room — small, and near the house

Zone 3 is capped by law, not by what a plant would like: Perth irrigation runs only on rostered days inside a fixed window, and stops altogether from 1 June to 31 August. That is the argument for keeping zone 3 small and putting it where it is seen. Rostered days, the winter switch-off and the new-garden exemption are in the sprinkler roster reference; the physical station-by-station design is in Irrigation 3.

Trees, by size and root behaviour

From Water Corporation’s Selecting the right tree guide, which scores 116 species. Ratings below are theirs; the shot-hole borer column is DPIRD’s.

Tree	Size	Drop rating	Roots	PSHB
Eucalyptus todtiana — coastal blackbutt	8–16 m	0	Low	Not listed
Eucalyptus marginata — jarrah	16 m+	0	Moderate	Not listed
Eucalyptus wandoo — wandoo	16 m+	0	Moderate	Not listed
Agonis flexuosa — WA weeping peppermint	8–16 m	0	Moderate	Not listed
Banksia grandis — bull banksia	8–16 m	0	Low	Not listed
Eucalyptus erythrocorys — illyarrie	4–8 m	0	Low	Not listed
Eucalyptus caesia subsp. magna — silver princess	8–16 m	0	Low	Not listed
Hakea laurina — pincushion hakea	4–8 m	1	Low	Not listed
Corymbia ficifolia — red flowering gum	—	—	—	High
Corymbia calophylla — marri	—	—	—	High
Banksia littoralis — swamp banksia	8–16 m	0	Low	High

That last block is the point of doing both checks. Marri, red flowering gum and swamp banksia are Perth staples; all three are rated high hosts by DPIRD, and swamp banksia sits on Water Corporation’s recommended verge list as well. DPIRD does not say never plant them — it says weigh “the risks and reward of planting species that may be susceptible to PSHB but also provide a demonstrated ecosystem service”. Say that out loud to the client and write the decision down.

Whatever you plant, the Utility Providers Code of Practice puts trees 2.7 m off the boundary and at least 0.5 m off water assets, and Before You Dig Australia comes before the shovel. See Locating services.

Shrubs and groundcovers by purpose

Drawn from Water Corporation’s four downloadable Perth and South West garden designs, with the plan each came from and its stated planting density (metres between plant centres).

Purpose	Species	Density	From
Screening / hedge	Alyogyne hakeifolia — native hibiscus	0.8–1.0 m	Native, Mediterranean
Screening / hedge	Westringia dampieri — shore westringia	0.8 m	Coastal
Structure, medium	Thryptomene saxicola — rock thryptomene	0.3–0.8 m	Native, Cottage
Structure, medium	Olearia axillaris — coastal daisy bush	0.8 m	Coastal
Structure, medium	Pimelea ferruginea — pink rice flower	0.6 m	Coastal, Cottage
Feature / colour	Anigozanthos flavidus — kangaroo paw	0.5 m	Native, Cottage
Strap / texture	Lomandra longifolia — spiny-headed mat rush	1.0 m	Native
Strap / texture	Dianella brevicaulis — coast flax-lily	0.4 m	Coastal
Groundcover	Hemiandra pungens — snake bush	0.8 m	Coastal
Groundcover	Carpobrotus virescens — pigface	1.0 m	Coastal
Groundcover	Kennedia prostrata — running postman	1.0 m	Cottage
Groundcover	Grevillea crithmifolia prostrate	1.0 m	Native

Two substitutions worth making. The Mediterranean plan includes Nerium oleander, which is poisonous in every part, and Olea europaea, which self-seeds into bushland — swap both on family gardens and bushland boundaries.

Phosphorus-sensitive plants

Perth’s sands hold almost nothing, so fertiliser either goes into the plant or into the river. SERCUL is blunt: garden fertilisers are “one of the largest threats to our rivers as nutrients added to our sandy soils are easily leached”, and its lawn benchmark is an N:P:K of 10:1:6.

The plants to watch are the Proteaceae. ANPSA names them directly — “many members of the Protea family such as Banksia, Grevillea, Telopea and Hakea” — and gives the two ratios you shop with:

Situation	N:P:K	Source
Many Australian plants, general purpose	about 12:14:10	ANPSA
Phosphorus-sensitive species	about 10:3:6	ANPSA
Perth lawn	10:1:6	SERCUL

Do not overstate it to a client. A sensitivity trial found “about 82% did not show any of the symptoms that are typical of phosphorus toxicity”, with Banksia, Hakea and Grevillea among the less affected genera. The practical rule stands anyway, because on this soil the low-phosphorus choice protects the Swan and Canning regardless of what it does for the plant. Kings Park’s own instruction for its banksias is simply a native slow-release fertiliser at planting and annually.

What varies by council, and how to get your answer

Verge species lists, height limits, whether a verge permit is needed, street tree programs and subsidised plant giveaways are all set by individual local governments; WALGA represents 139 of them. Water Corporation only goes as far as saying every Gold Waterwise Council has a verge policy or guideline. Find your client’s council in the WALGA directory, search its site for “verge” and “street tree”, and put the printed policy in the job file. See also Perth soils for what your dune system will hold, and the Noongar six seasons for when to plant it.