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.

Administration car park closure

There will be limited access to the BGPA Administration building and the Kings Park Education and Learning building from Wednesday 15 June 2022 for approximately 8 weeks, due to ongoing Water Corporation works.

Water Corporation works

The Water Corporation is replacing approximately 700 metres of ageing water pipes between Mount Eliza Reservoir and Bellevue Terrace in Kings Park.

Bold Park disruption

Banksia Carpark in Bold Park is currently closed to the public due to stormwater damage.

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Floral clock debuts artistic new look

The much-loved Kings Park Floral Clock has debuted a whole new look with a modern floral makeover from an exciting artist.

Fire Ecology Burn

Researchers and bushland staff at Kings Park successfully carried out a scientific research burn in a section of Kings Park bushland earlier this month. 

New innovative AR experience launched at Kings Park

A new locally developed augmented reality experience has been launched at Kings Park in time for families to enjoy during these school holidays.

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