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Blackberry - Identification | LC0188 |
Department of Primary Industries
Updated: September 2007
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This Information Note describes the weed blackberry, Rubus fruticosus.
See the Information Note LC0381 Blackberry – Management for information about the management of this weed.
Common and Scientific Names
- Rubus fruticosus Linnaeus aggregate
- Blackberry, European blackberry
- Family Rosaceae (rose family)
The botanical name indicates a number of closely related species which for convenience are dealt with (aggregated) under one name. At least nine species in the aggregate, some with subspecies, and possibly hybrids occur in Victoria.
All of these species, except Rubus ulmifolius, produce seed asexually in a process by which pollen stimulates the seed to develop without fertilisation, so that the seed is a genetic replicate, or clone, of the mother plant. Most European blackberry species appear to exist as single clones in Australia.
Origin and Distribution
All the weedy blackberry species found growing in the wild in Australia are of European origin. Blackberry can be found in areas with greater than 760 mm annual rainfall, mainly on fertile soils. The blackberry aggregate has probably reached the climatic limits (rainfall and temperature) of its potential range in Victoria, however, individual species have not: some are widespread, others still very restricted in distribution.
Description
A perennial, semi-deciduous, prickly, scrambling, semi-prostrate to almost erect shrub, with arching and entangling stems arising from a woody crown; forming thickets up to several metres high. Reproduces by seed and root suckers and by daughter plants when stem tips contact the soil. The root/crown system is the only perennial part of the plant.
Stems - erect or semi-erect canes, arched or trailing, up to 7 m long, green, purplish or red, smooth or moderately hairy, round or angled, with numerous curved or straight prickles of different sizes, and sometimes with small stalked glands. The canes are normally biennial, dying off after fruiting, but may occasionally live longer. Canes that have arisen from the crown in the current year (first year canes, known as primocanes) usually do not produce flowers. Second year canes (floricanes) grow as side shoots from the primocanes during their second year of growth and bear the flowers and fruit.
Leaves - alternate, compound, with 3 or 5 oval leaflets. Leaves on primocanes mostly with 5 leaflets, those on floricanes mostly with 3 leaflets. Simple leaves (not divided into leaflets) often occur near the flowers. Leaflets usually dark-green above and lighter green beneath, with small teeth around the edges. Underside covered with whitish hairs in some species. Short prickles on the leaf stalks and the underside of veins. Usually shed or partially shed in winter.
Flowers – 2 to 3 cm in diameter, growing in clusters on side branches of floricanes; 5 sepals and 5 white or pink petals, numerous stamens.
Fruit - a berry, 1 to 3 cm in diameter, changing colour from green to red to black as it ripens; each berry an aggregate of many single-seeded juicy segments (drupelets). Late December until April.
Seeds - deeply and irregularly pitted, light to dark brown, oval, 2 to 3 mm long.
Roots - main root from a crown up to 20 cm in diameter, vertical to a maximum depth of 1.5 m depending on soil type. Numerous secondary roots horizontally from the crown for 30 to 60 cm and then vertically down. Many thin roots in all directions from the secondary roots.
Species in the Aggregate
In Eurasia there are over 2000 named entities in the Rubus fruticosus aggregate, arranged into 66 relatively distinct species. All have compound leaves and ripe fruit that are black and remain attached to the receptacle (the central and basal axis of the fruit). The species comprising the aggregate that are currently recognised as being present in Victoria are:
- R. anglocandicans (previously as R. procerus, R. discolor, R. chloocladus and R. ulmifolius hybrids)
- R. cissburiensis
- R. echinatus
- R. erythrops (previously as R. rosaceus)
- R. laciniatus
- R. leucostachys (previously as R. chloocladus)
- R. polyanthemus
- R. ulmifolius
- R. vestitus
Identification of the particular species present at a site can be important because they do not all respond similarly to control measures. In particular there is wide variation is their susceptibility to strains of the biological control agent, blackberry leaf rust Phragmidium violaceum.
R. anglocandicans, R. polyanthemus, R. ulmifolius and R. laciniatus are the most widespread species, but R. cissburiensis, R. anglocandicans and R. rosaceus were ranked as the most damaging weeds, based on their height, radius, daughter plant production and suckering ability, prior to the introduction of the rust. R. anglocandicans is relatively easily recognised by its large, mostly white flowers, with round, non-crumpled petals, its stout, furrowed, hairless, dark wine-red stems, 6-10 mm in diameter, bearing strong prickles, and leaves that are whitish beneath due to a dense covering of short, woolly hairs.
Identifying blackberry species can be difficult. A magnifying lens is usually needed (standard 10x hand lens is suitable), along with specimen material consisting of a central piece of a mature primocane with thorns and leaves, and a section of floricane with flowers or young fruit. Petal colour of the flower when in bud and in the mature state should be noted. Specimens growing in full sunlight should be used for identification.
Most species can be identified by reference to the Flora of Victoria (Jeanes and Jobson 1996) or Bruzzese and Lane (1996) but see the above list for the currently recognised names. The best resource for identification is the illustrated interactive computer key of Barker and Barker .
Similar native species
Care should be taken to distinguish the three native Rubus found in Victoria, all of which have red or orange fruit that fall away from the receptacle when ripe.
Two are restricted to forests of eastern Gippsland, east from Maffra (Queensland bramble R. moluccanus and rose-leaf bramble R. rosifolius), and the other is common through most of the southern half of the State and the North East (small-leaf bramble or native raspberry R. parvifolius). The latter species crosses with R. moluccanus to form the rare hybrid R. x novus, also known from Victoria.
Queensland bramble leaves are not divided into leaflets, but may be shallowly 3-5 lobed. Rose-leaf bramble has stems, leaf stalks and sepals densely covered with long, reddish, gland-tipped bristles, and a leaf with 3 leaflets. Small-leaf bramble has densely hairy young canes, leaves almost hairless on the underside, and abundant, small, strong, hooked, stem prickles.
Other similar species
Other Rubus species that are not part of the R. fruticosus aggregate have been noted in small naturalised populations in Victoria or have occasionally been found as garden escapes. These include raspberry R. ideaus, wine raspberry R. phoenicolasius, keriberry R. rugosus and North American blackberry species that are commercially cultivated for their fruit. The North American species have non-paniculate flower heads, longer flower stalks, and glands on the primocanes. So-called "thornless blackberries" are part of a large complex of Rubus hybrids derived from several different species over a long period by commercial breeders. They have complicated pedigrees which include both European and American blackberry species. Possibly these varieties can cross with other species of European blackberry and create new hybrids. Thornless blackberries are not recorded as weeds in Australia.
European blackberry may also be confused with species of Rosa, including sweet briar Rosa rubiginosa, a declared noxious weed, and the dog rose Rosa canina. The fruit of these roses is an orange, red or almost black ‘hip’, not an aggregate of small fleshy segments as in Rubus, and they have prickles that become readily detachable with age.
Flowering Period | Figure 1. left, photo of blackberry flower. Figure 2. right, illustration of fruit and leaves of the divided leaf form of cutleaf blackberry, Rubus laciniatus.
Figure 3. Blackberry bush.
Figure 4. Typical form of blackberry, Rubus fruticosus.
Figure 8. Records of blackberry in Victoria.
Figure 5. Blackberry growth form.
Figure 6. Primocanes with young side shoots that will form the floricanes.
Figure 7. Left to right: leaves of Rubus laciniatus, R. anglocandicans and R. cissburiensis; top row: upper sides; bottom row: undersides. |
Mainly summer. Late November-early February.
Lifecycle
Seeds germinate mainly from September to November. Germination rates are low (around 30% of seed), but are markedly higher for seed that has been eaten and voided by birds or mammals. Approximately 1% of seed germinates in the first year, and 10% within three years. The longevity of seed in the soil is currently unknown. Seedlings do not survive in areas with moderate or heavy shade. Seedlings are not very vigorous in their first year but after a woody crown is formed they become firmly established.
New canes are produced from the crown each spring and frequently project horizontally for over 3 m from the crown after one growing season. Canes in their first year of growth (primocanes) do not flower or fruit, but can produce daughter plants where they touch the ground in autumn. Daughter plants are usually produced close to the tip of the cane, and the cane tip can continue to extend after the daughter plant is formed. In their second year, the primocanes produce side shoots (floricanes) that bear flowers, and fruit from late December to April.
Canes that have borne fruit usually die back to the crown over autumn and winter, and leaves may be shed in winter, leaving a plant with living, year-old primocanes and daughter plants that are growing independently. Daughter plants produce first year canes the following spring.
Habitat and Land Use
Throughout all the higher rainfall (over 760 mm annual average) regions of Victoria, particularly in bushland, forest plantations, along streams and on grazing land.
Dispersal
Fruit are eaten by birds, foxes and other mammals which distribute seeds over wide areas. Seeds are transported by water along creeks, drains and rivers. Movement of contaminated soil and cultivation also spread blackberry. Infestations increase in size by the formation of daughter plants at the ends of canes, up to 6 m from the crown.
References
- Amor, R.L., Richardson, R.G., Pritchard, G.H. and Bruzzese, E. (1998) Rubus fruticosus L. agg. Pp. 225-246 in F.D. Panetta, R.H. Groves and R.C.H. Shepherd (Eds.) The Biology of Australian Weeds Volume 2. Melbourne, R.G. & F.J. Richardson.
- Barker, R.M. and Barker, W.R. (2004). Blackberry: an identification tool to introduced and native Rubus in Australia. CD-ROM, Adelaide, State Herbarium of South Australia. Electronic Flora of South Australia (external link).
- Bruzzese, E. and Lane, M. (1996) The Blackberry Management Handbook. Melbourne, Keith Turnbull Research Institute, Department of Conservation and Natural Resources.
- Evans, K.J., Symon, D.E. and Roush, R.T. (1998) Taxonomy and genotypes of the Rubus fruticosus L. aggregate in Australia. Plant Protection Quarterly 13: 152-156.
- Evans, K.J. and Weber, H.E. (2003) Rubus anglocandicans (Rosaceae) is the most widespread taxon of blackberry in Australia. Australian Systematic Botany 16, 527-537.
- Jeanes, J.A. and Jobson, P.C. (1996). Rosaceae. Pp. 556-584 in N.G. Walsh & T.J. Entwisle (Eds.), Flora of Victoria Volume 3. Dicotyledons Winteraceae to Myrtaceae. Melbourne, Inkata Press.
- McGregor, C. (1998) Relationships between weedy and commercially grown Rubus species. Plant Protection Quarterly 13: 157-159.
- Parsons, W.T. and Cuthbertson, E.G. (2001) Noxious Weeds of Australia. 2nd Ed., Collingwood, Vic., CSIRO Publishing.
Acknowledgements
Compiled by Ian Faithfull with assistance from El Bruzzese, Franz Mahr, Sarah Keel. Figures 6 and 7 by Franz Mahr. Map by John Weiss. Updated by Melanie Martin, DPI, August 2006. Updated by Andy Wernert, DPI, September 2007.
The advice provided in this publication is intended as a source of information only. Always read the label before using any of the products mentioned. The State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication.
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