Quick Facts

Quick facts

• Romulea species (Romulea spp.) are small perennial herbs arising from bulb like underground stems (corms) with annual leaves and small pink, white, purple or yellow flowers.
• Four species are naturalised in Australia, of which R. rosea var. australis and R. rosea var. communis are the most widespread.
• They are common weeds of lawn, pasture, sports fields, pathways, roadsides and woodlands.
• Romulea species are best controlled with herbicides.

What Does It Look Like?

What is it?

Romulea species (Romulea spp.) are small perennial herbs arising from corms (short fleshy underground stems) which produce new stems and leaves annually. Romulea species have a small number of very tough, usually prominently grooved, flat or rounded leaves that mostly arise from the base of the plant. Stem leaves where present, are smaller.

Flower-heads have one or more terminal stalked flowers, each with two floral bracts (modified leaves below flower-head). Flowers are regular in shape, bisexual, with a short funnel-shaped tube and with six equal and spreading lobes or petals.

Fruit is a 3-celled capsule, enclosed within the floral bracts, and contains numerous red-brown seeds (Cooke 1986; Wheeler et al. 2002).

Four species of Romulea occur in Australia. The most common is Onion Grass or Guildford Grass (R. rosea) which grows to 40 cm high with petals up to 18 mm in length (Hussey et al. 1997). There are three varieties in Australia: R. rosea var australis, with pink to purple, rarely white, flowers and a yellow throat, R. rosea var. communis with darker, magenta-pink flowers and a violet-blue or black band above the yellow throat (Wheeler et al. 2002) and R. rosea var. reflexa. R. rosea var. reflexa has been recorded as a garden escapee in Melbourne but is not known to be naturalised in Australia. It has larger magenta flowers with the floral bracts intricately veined outside (Cooke 1986).

R. flava var. minor has yellow flowers with petals up to 15 mm long. R. flava var. flava is occasionally cultivated as an ornamental and has a flower that is over 2.5 cm long, but is not naturalised in Australia (Cooke 1986). R. minutiflora has pale pink to lilac flowers with a dull yellow throat, petals up to 9 mm long with more rounded tips than R. rosea. R. obscura is similar to R. rosea but has pale orange-brown to terracotta flowers, with a dull yellow and purple striped throat (Cooke 1986).

For further information and assistance with identification of Romulea spp., contact the herbarium in your state or territory.

Flower colour

Yellow, White, Purple, Pink

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Romulea species are common weeds of lawn, pasture, sports fields, pathways, roadsides and woodlands (Cooke 1986; Hussey et al. 1997; Spooner et al. 2007; Tamar Valley Weed Strategy undated).

In Western Australia, Romulea rosea is a common lawn and pasture weed and is ubiquitous in most woodlands, on granite rocks, limestone heath and clay wetlands throughout the south-west. R. flava is found in Banksia and Eucalypt woodlands, and sedgelands. R. minutiflora is found in eucalypt woodlands and R. obscura in woodlands and heath (Hussey et al. 1997).

Are there similar species?

The most similar plants to Romulea species are the closely related minor weeds Blue Pigroot and Scourweed (Sisyrinchium spp.). They have small, cream, six-petalled tubular flowers with a purplish centre marking and a central stripe on each petal and the small spherical fruit are striped in maroon and cream. The leaves are flattened and grass-like (STSCNPC undated).

Why Is It A Weed?

What are its impacts?

Urban environments: Romulea species are common weeds of lawn (where their tough leathery leaf blades readily blunt mower blades) pasture, sports fields, pathways, roadsides and woodlands (Cooke 1986; Hussey et al. 1997; Spooner et al. 2007; Tamar Valley Weed Strategy undated). Animals rarely graze the plant (Tamar Valley Weed Strategy undated) and fibre balls can form in the stomachs of livestock that eat it (Blood 2001).

Native ecosystems: In Western Australia, Romulea rosea is a common lawn and pasture weed and is found in large quantities in most woodlands, on granite rocks, limestone heath and clay wetlands throughout the south-west. R. flava is found in Banksia and Eucalypt woodlands, and sedgelands. R. minutiflora is found in eucalypt woodlands and R. obscura in woodlands and heath (Hussey et al. 1997).

How does it spread?

Romulea species' seed is presumed to be mostly spread by mowing and slashing of infested areas. Both corms and seeds may be dispersed by dumping of seed or corm-bearing garden waste and the movement of contaminated soil. Water may also transport seeds short distances (STSCNPC undated; Tamar Valley Weed Strategy undated).

What is its history in Australia?

It is not known when or how Romulea species arrived in Australia but the earliest herbarium records for Romulea rosea are for plants collected in Victoria, Western Australia and Tasmania in the time period shortly before 1900. Romulea minutiflora was collected in the Wimmera region and Port Phillip, Victoria in the 1890s (National Herbarium of Victoria 2008).

How To Manage It?

Best practice management

Non-chemical control: Romulea rosea is extremely difficult to remove once an infestation has become established. Physical removal is difficult as the bulb-like underground stems (corms) may occur to a depth of 200 mm. Pulling on the leaf blades usually snaps them off at the top of the corm, leaving the corm in the soil. Cultivation is seldom useful as a control method and in fact may assist their dispersal by breaking up and distributing the corm. Limited success may be obtained where the corms can be brought to the soil surface to dry out in summer (Tamar Valley Weed Strategy undated).

Chemical control: Spot spraying is recommended, with a registered herbicide, just on flowering time when corm exhaustion occurs (Brown & Brooks 2002).

These control methods are also likely to be effective on other Romulea species.

Please see the Australian Pesticides and Veterinary Medicines Authority at for chemical information http://www.apvma.gov.au 

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Romulea species reproduce via corms and by seed (Blood 2001). R. rosea flowers open first at ground level. As it matures, the flower stem elongates and bends over, eventually pushing the seed capsule back under the surrounding vegetation. Eventually the capsule dries and splits open, releasing the seeds. Seeds germinate in autumn to winter and flowering occurs in spring. (Hussey et al.1997; Tamar Valley Weed Strategy undated).

The corms of weedy Romulea plants are summer-dormant in Western Australia, sending up their first shoots as the temperature drops with the autumn rains. Each year a new daughter corm (sometimes two), is formed as the plant is actively growing. Meanwhile the parent corm slowly exhausts and dies (Brown & Brooks 2002).

Where Is It Found?

Which states and territories is it found?

ACT, NSW, SA, TAS, VIC, WA

What areas within states and territories is it found?

Both varieties of Romulea rosea occur in all Australian states and territories except for the Northern Territory (AVH 2008). They are naturalised in south-western Western Australia from Jurien Bay to Albany, in south-eastern South Australia from Yorke and Eyre Peninsulas, in south-eastern New South Wales, in northern and eastern Tasmania, is widespread in Victoria and there are isolated occurrences in Queensland (AVH 2008; Cooke 1986).

R. minutiflora occurs in South Australia from Eyre Peninsula and Flinders Range to the south-east, the Riverina district of New South Wales and western and central Victoria. There are no records in Tasmania or Queensland and only one record in Western Australia (AVH 2008; Cooke 1986; Spooner et al. 2007).

R. flava var. minor is naturalised in parts of south-western Western Australia and found locally in New South Wales and Victoria (AVH 2008).

R. obscura is naturalised in a few localities near Perth in Western Australia (AVH 2008; Cooke 1986; Spooner et al. 2007).

Where does it originate?

There are about 90 species of Romulea, all from the Cape Province in South Africa, a number of which are naturalised in Europe, the British Isles, the United States of America, New Zealand and Australia (GRIN 2008).

The plant naturalised in North America is R. rosea var. australis but it does not appear to be weedy in the parts of California where the species occurs (Goldblatt undated).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Romulea spp.

Other scientific names (synonyms)?