Common name: Purple flag, Native Iris; Noongar name: Komma


Patersonia occidentalis, Purple flag. Photo: D. Blumer.View image slideshow

Origin of Scientific Name

Patersonia – after William Paterson (1755-1810), commander of the military force in NSW; one of the earliest botanists of the colony, and a friend of botanist Robert Brown to whom he sent specimens.

occidentalis – (Latin) western; used in comparison to other species or geographical areas, referring to the State of Western Australia where the species is found.


Patersonia occidentalis is a strappy leaf, tufted perennial herb that grows to 80 cm high and up to 60 cm wide. It can be found naturally amongst granite outcrops and on dunes from the Murchison River to east of Esperance.

It’s striking three-petalled flowers in blue, violet or purple appear in late spring to early summer, but can appear at other times throughout the year. These flowers are held above the foliage for a stunning display that also attracts native bees. Interestingly, individual flowers open for less than one day; however, many flowers are produced from the one stem and a well grown plant will produce a large number over the season, making them a most attractive addition to the home garden.

Horticultural tips

  • Propagate from seed sown in May and June.
  • Plant in a sunny position.
  • Best mass planted in drifts and used as a border plant with Pimelea ferruginea and Leucophyta brownii.
  • For improved display, replace plants every three to four years.

For more horticultural tips view our Plant Notes section.

View in Kings Park

Visit Kings Park to see Patersonia occidentalis at the entry to the Western Australian Botanic Garden and in Northern Wheatbelt garden beds along Forrest Drive (refer to map).

Want more information?

Refer to the profile for this plant on the Department of Biodiversity, Conservation and Attractions' FloraBase online herbarium.

Purple Flag in a garden bed in Kings Park. Photo: D. Blumer. Patersonia occidentalis. Photo: D. Blumer.

Event disruptions

Poolgarla Parkland will be fenced off and there will be additional foot traffic and noise around Poolgarla Family Area from Monday 28 November to Friday 2 December 2022 due to the Danjoo Koorliny event.

Naturescape summer opening hours

Summer opening hours for Rio Tinto Naturescape Kings Park will be taking effect from 5 November 2022.

Polyphagous Shot-Hole Borer

The Department of Primary Industries and Regional Development (DPIRD) is responding to the confirmed detection of an exotic beetle, the Polyphagous Shot-Hole Borer (PSHB) in the Perth metropolitan area.

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The Festive Floral Spectacle celebrating our blue kangaroo paw has launched in the State Buildings!

Flowers in Focus 2022 winners

Thank you to everyone who entered our Flowers in Focus photography competition this year.

New Bold Park Management Plan

The Bold Park Management Plan 2022 - 2027 has been published by BGPA after a period of extensive public consultation

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