Quick Facts

Quick facts

• Originally from East Africa and tropical Asia, Barleria (Barleria prionitis) is a robust prickly shrub that grows up to 1.5 m tall.
• The dense prickly thickets which Barleria forms are undesirable for economic and environmental reasons.
• Barleria is a weed of waterways, open woodlands, roadsides, disturbed sites, waste areas and overgrazed pastures in tropical regions.
• Barleria is difficult to eradicate once established, but early intervention is effective.
• It has medicinal and antiseptic properties which may be able to be exploited if the plant continues to spread.
• If you see a plant that may be Barleria, contact your local council or state territory weed management agency.

What Does It Look Like?

What is it?

Barleria (Barleria prionitis) is a robust prickly shrub to 1.5 m tall. Its branches are hairless and have 2–5 spines each 10–20 mm long at the base of leaves and branches. Its leaves are oval in shape and up to 130 mm long and 40 mm wide. The edges of the leaves are smooth but the apex is spine-tipped. Hairs may be found either all over the leaf or only on the midrib, edges and main lateral veins (Barker 1986; CRC 2003).

The yellow-orange, tubular flowers are about 40 mm long and grow in bunches at the ends of branches, sometimes with some single flowers at the leaf bases below. Each flower has a leaf-like bract and a pair of spreading spines at its base. There are 4 stamens but only 2 of them protrude beyond the petals (Barker 1986; CRC 2003).

The seed capsules (fruit) are about 18 mm long, hairless and contain 2 flat seeds, measuring about 8 mm by 5 mm. The seeds are covered in long hairs which becoming mucilaginous when wet (Barker 1986).

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

Flower colour

Yellow

Growth form (weed type/habit)

Shrub

Where it currently grows? Preferred habitat

Barleria grows on a wide variety of soils and seems to prefer well-drained areas. In the Katherine area it has been recorded from rugged limestone outcrops in very little soil, presumably extracting moisture by a network of roots into rock crevices. It occurs in savanna country, along river banks and, on Boigu Island, in sand. It is also recorded from disturbed areas such as roadsides or overgrazed pastures (CRC 2003).

Are there similar species?

There are 5-6 known species of Barleria in gardens in Australia. Amongst these B. strigosa (blue or lavender flowers), B. lupulina (yellow flowers), B. cristata (white or purple flowers), B. repens (red flowers), B. obtusa (blue, lavender or white flowers) and possibly B. albostellata (white flowers) have occasional records as garden escapes. B. lupulina is the only species likely to be confused with Barleria since it shares the yellow flowers but its leaf has a red midrib. It is grown in gardens throughout the tropics and is as undesirable as Barleria as a garden escapee (Barker 1986 and 2007, pers. comm.).

Why Is It A Weed?

What are its impacts?

Barleria is on the Alert List for Environmental Weeds, a list of 28 non-native plants that threaten biodiversity and cause other environmental damage. Although only in the early stages of establishment, these weeds have the potential to seriously degrade Australia's ecosystems (CRC 2003).

Agriculture: The dense, prickly thickets that it eventually forms are potentially environmentally and economically damaging. Cattle do not eat Barleria, and their movements, as well as those of other animals, may be impeded where it occurs around waterways. It can also provide refuges for feral animals.

Native ecosystems: Barleria is found in natural ecosystems, such as open woodland or along watercourses, in the Northern Territory, where it can be very persistent and difficult to remove. While it is not particularly active in the dry season it becomes extremely vigorous with the onset of the wet.

Human impacts: Clearly it is not desirable in areas of human recreation and may reduce the capacity for indigenous people to exploit natural resources in infested areas (CRC 2003). The spines of Barleria stems can also cause injury (Weeds of Australia, 2016).

How does it spread?

Dispersal is by seeds, one plant producing up to hundreds of seeds in a season. It is not known how long the seeds remain viable in the soil after being dropped but it is likely to be at least several years. Many plants that are closely related to Barleria are capable of vegetative reproduction when cuttings or stem fragments encounter a suitably moist environment that allows them to start growing roots. Barleria can probably also reproduce vegetatively (CRC 2003). As with most members of the family Acanthaceae, mature capsules explode and fling out their seeds; the signal to do this is often wetting of the capsule after a dry period (Barker 2007, pers. comm.).

Although most seeds germinate within a few metres of the parent plant, infestations can move relatively quickly downhill, where seed transport may be aided by water. Also, as seen in the Torres Strait infestation, seed spread may be quicker along paths or roads (CRC 2003).

Because of the ability of Barleria to grow roots from any node of the plant care needs to be taken that garden waste is treated before it is discarded. All known occurrences in Australia appear to have been from discarded garden plants (Barker 2007, pers. comm.).

What is its history in Australia?

The date of Barleria's original arrival in Australia is not known. Because of its wide use as an ornamental and hedge plant and the establishment of the Victoria River Downs populations from discarded pot plants by the 1960s it is likely that it was introduced to Australia at least by the early 1900s (Barker 1986).

It is used as a hedge plant. It is also possible that it may have been introduced to Australia because of its well known medicinal and antiseptic properties, including treating fever, respiratory diseases, tooth ache, joint pains and a variety of other aliments (CRC 2003; Francis undated).

How To Manage It?

Best practice management

Experience throughout Australia has shown that if the willingness and resources exist, Barleria can be relatively easily controlled, especially if it is attacked while infestations are still small. Do not try to control Barleria without expert assistance. Control effort that is poorly performed or not followed up can actually help spread the weed and worsen the problem (CRC 2003).

Chemical control: can be effective in controlling Barleria. It is thought that mowing, followed by a spraying of any newly emergent plants with a broadleaf herbicide, is likely to be effective. Success was achieved with herbicide on the Kimberley and Katherine populations.

Non-chemical control: Physical control: Pulling by hand is effective where the population is small but gloves are needed due to the spiny nature of the plant and correct disposal of the pulled plants is essential (CRC 2003).

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

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Barleria is considered to be a perennial species because it lives for more than one year. It is well adapted to the climate of northern Australia, which has distinct wet and dry seasons. During the dry season when virtually no rain falls (generally May- September), its stems, leaves and flowers die off although the roots remain alive. The vegetation then regrows after the first rains of the wet season, and it flourishes during the remainder of the wet season. Dieback of above-ground vegetation on Boigu Island in the Torres Strait generally occurs between September and November, a little later than on the mainland.

Seeds germinate early in the wet season, following the first significant storms, and grow steadily during the remainder of the wet season. It is not definitively known how old seedlings are before they first flower. In Katherine plants do not flower until they are at least half a metre tall and their estimated age is one year. In northern Australia flowering occurs at the end of the wet and start of the dry season (typically April-May). Fruiting occurs several months after flowering, at the end of the dry season. Seeds germinate fairly soon after they are dropped, soil moisture permitting.

On Boigu Island Barleria is thought to flower and fruit over a more extended period. This is probably related to the climate, which has more regular rainfall and shorter dry seasons than on mainland northern Australia.

Barleria plants can probably live for about ten years in good conditions (CRC 2003).

Where Is It Found?

Which states and territories is it found?

NT, QLD, WA

What areas within states and territories is it found?

Most recorded infestations in Australia have been traced back to escapees from gardens. Barleria was originally recorded in Northern Territory at Darwin and in the Victoria River Downs Station area where it probably arose from discarded pot plants in the area surrounding the old 1920s hospital on Wickham River. It has also been found around Berry Springs, Katherine and Mataranka.

A population from waste places on the Ross River in Townsville has apparently now been eradicated, but the Victoria River Downs plants persist, though under "active control" (Waterhouse 2004, pers. comm.). Barleria has escaped into a creek at Argyll Diamonds in the East Kimberley (Mitchell 2004, pers. comm.). A small naturalised population originating from dumped garden plants occurring on a sand spit on Boigu Island in the Torres Strait appears to be spreading (Barker 2007, pers. comm.).

Barleria is well adapted for the wet-dry tropics of northern Australia and has the potential to spread throughout that region (CRC 2003).

Where does it originate?

Barleria occurs naturally throughout East Africa, tropical Asia, including India, Indonesia, Malaysia and the Philippines. It is a weed in parts of tropical America (Puerto Rico) and in Hawaii (Francis, undated).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NT, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

YES

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

Barleria prionitis

Other scientific names (synonyms)?

Does it have other known common name(s)?

Porcupine Flower