Quick Facts

Quick facts

• Buffalo Burr (Solanum rostratum) is a prickly annual herb with yellow flowers and very spiny, dry fruits.
• It is found in the wheatbelt areas of southern mainland Australia.
• It is a minor weed mainly on cropping and pasture land, but also on roadsides.
• Effective seed dispersal occurs by attachment of burr fruit to wool (on sheep), on clothing and other fabrics and also when the spent plant is blown around, shedding seed.
• The prickly fruits can cause physical injury to humans and stock.

What Does It Look Like?

What is it?

Buffalo Burr (Solanum rostratum) is a sprawling annual herb that grows commonly around 0.2–0.4 m high and diameter, but may at times reach 1m high and diameter. The stems are mid to greyish green, with a covering of minute star-shaped hairs as well as unbranched sticky hairs; they also bear fairly frequent sharp, straw-coloured prickles up to 10 mm long. The  leaves are arranged alternately along the stem, they are stalked (the stalks up to 50 mm long), mid green or greyish-green above and below, with a covering of hairs as on the stems; they are ovate in outline (oval with the widest point below the middle), sometimes narrowly so, 20–100 mm long and 10–80 mm wide, deeply lobed (cut from three quarters of the way to almost all the way to the midrib), with 3–4, wavy-edged, rounded lobes on each side; they also have numerous straight, needle-like prickles up to 6–10mm long on both the upper and lower surfaces. 

The flowers are borne in stalked clusters of 5–10 on the stem between the leaves, often below the base of every second leaf; they are shortly stalked, saucer-shaped with a wavy edge and up to 15 short lobes (some rounded, some angled), entirely yellow (including the anthers at the centre). The green calyx (cup-shaped outer covering at the base) has 5 long lobes and is very prickly, being densely covered in prickles up to 10 mm long.

Most of the flowers in each cluster develop into fruits. The fruits are dry, globular and entirely enclosed by the enlarged calyx which forms a casing of impenetrable prickles; each fruit contains 50–120 seeds. The seeds are roughly circular, wrinkled, with a finely pitted surface,  dark brown to black and 2-3 mm diameter. With age, the spiny covering decays and, when the wind blows the old plants along the ground, the seeds are shaken out.  (Symon 1981; Purdie et al. 1982; Parsons & Cuthbertson 2001; Bean 2004).

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

Flower colour

Yellow

Growth form (weed type/habit)

Robust, sprawling annual herb

Where it currently grows? Preferred habitat

Buffalo Burr grows in sub-humid temperate to warm-temperate regions, with an annual rainfall of 400-700 mm. It prefers open disturbed habitats where soil nutrients are relatively high. It has become naturalised in paddocks and fallow areas after removal of crops (Parsons & Cuthbertson 2001) as well as along roadsides.

Are there similar species?

The leaves of Buffalo Burr are similar to Solanum sisymbriifolium, but that species is a shrub over 1 m high with white flowers and bright red, fruits with only a few small prickles at the base (Symon 1981; Bean 2004).

Why Is It A Weed?

What are its impacts?

Agriculture: Buffalo Burr is principally a weed of pastures and crops but widely adopted pasture and cropping practices (using herbicides) mean that its impact is only on a minor scale. It has been recorded as causing physical injury to stock (especially around the nose and mouth), stock poisoning (all parts are toxic) but records are few; and as a contaminant of cereal seed. Buffalo Burr also has the potential to be problematic as a host for the Colorado Potato Beetle, a major pest of potato crops, and as a host for nematodes that affect tomatoes and tobacco in North America (Parsons & Cuthbertson 2001).

General:  Buffalo Burr has been recorded as a weed of roadsides, mostly in cereal growing areas, but also in urban situations, where it is capable of causing physical injury to humans.

How does it spread?

The spiny burr-like fruits of Buffalo Burr may be dispersed by attachment to animal fur, wool and clothing. Old plants can blow along the ground, allowing the release of seeds from disintegrating fruits (Parsons & Cuthbertson 2001).

What is its history in Australia?

Buffalo Burr was first recorded as a naturalised plant in 1904 (Maiden 1904). It was presumably accidentally introduced, as there is no record of intentional introduction. It was probably imported as seeds contaminating cereal grain (Parsons & Cuthbertson 2001).

How To Manage It?

Best practice management

Non-chemical control: Manual control: If practical, Buffalo Burr plants can be manually removed; this particularly effective if it is done before they develop seeds. Ploughing or tilling will remove larger infestations.

Chemical control: Some herbicides kill seedlings but not older plants, while other herbicides are effective on more mature plants (Parsons & Cuthbertson 2001).

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)

Buffalo Burr seeds germinate in autumn and plants develop rapidly during winter, producing flowers in late spring and summer. Plants generally die in late summer (Parsons & Cuthbertson 2001). Seeds can remain viable for many years (Bean 2004).

Where Is It Found?

Which states and territories is it found?

ACT, NSW, QLD, SA, VIC, WA

What areas within states and territories is it found?

Buffalo Burr is naturalised  Western Australia, chiefly in the south-western wheatbelt; on Eyre Peninsula, in the mid north and in the Murray Plains of South Australia; in western and northern Victoria; mostly on the western slopes of the Great Dividing Range in New South Wales; and at a few scattered sites in south-eastern Queensland. 

Where does it originate?

Buffalo Burr is native to Mexico and southern United States (Symon 1981; Bean 2004; CABI Invasive Species Compendium 2019).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, VIC, 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

Solanum rostratum

Does it have other known common name(s)?

Pincushion Nightshade, Watermelon-leaved Nightshade