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.

Kings Park access disruption

Part of the Western Path between Monash Avenue and Aberdare Road will be closed from Monday, 8 February 2021 due to construction works on The Kids’ Bridge, pedestrian detours will be in place.

DNA Tower closure

The DNA Tower in Kings Park will be closed from Monday, 8 February 2021 until mid-April 2021 due to maintenance.

Concert traffic interruptions

Road and carpark closures will occur in Kings Park and Botanic Garden in February-March 2021 due to concert events.

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Farewell and thank you Grady and Lesley

The Botanic Gardens and Parks Authority (BGPA) would like to extend a sincere thank you and farewell to two of our longest serving staff members, Lesley Hammersley and Grady Brand who will retire from the Authority in December 2020.

Noongar Boodja Six Seasons is back!

Kings Park Education is excited to open bookings for our 2021 program of Noongar Boodja Six Seasons festivals, a celebration of Aboriginal culture, proudly presented by Fugro.

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