Sweet Briar

Rosa rubiginosa L.

Synonyms - Rosa eglanteria.

Family: - Rosaceae.

Names:

Rosa is Latin for rose.

Rubiginosa is from the Latin rubiginosus meaning rusty red and probably refers to the orange red fruit or the reddish hairs on the calyx and leaves.

Sweet Briar because the leaves when crushed and flowers have a sweet fragrance. Briar is from the Old English brer or braert and is a name for thorny shrubs.

Other names:

Eglantine (UK)

Sweet Brier (NZ)

Sweet Brier Rose (USA).

Summary:

Pleasantly aromatic, erect, woody, deciduous shrub or hedge plant, 1-4 metres tall with leaves composed of 5-9 toothed leaflets. Suckering occurs freely from the crown and bushes often exceed 1 metre in diameter at the base. It has pink or white flowers with 5 overlapping petals from October to December on a spiny flower stalk.

Description:

Cotyledons:

Two.

Leaves:

Alternate. Compound, pinnate, with 5-9, short stalked, leaflets. Sweet apple-like fragrance when rubbed. Fall off in winter(deciduous).

Stipules - Leafy and attached to the petiole.

Petiole - Spiny with many, curved thorns and glandular hairs.

Blade - Of leaflets, oval to egg shaped, 8-40 mm long by 8-15 mm wide, edges serrated or multi toothed. Almost hairless on top, hairy underneath with soft and glandular hairs. Glandular hairs on the teeth and edges. Terminal leaflet is larger than the side leaflets and its tip is more pointed. Spiny on the midrib.

Stems:

Many arising from the base, 1000-3000 mm tall, smooth when young becoming woody and rough with age. Short branches, which tends to curve upward, are carried towards the top of the stem. Many, backward directed, curved, stout thorns, to 18 mm long, and glandular hairs.

Flower head:

Loose clusters of 1-3 flowers in a corymb on short side shoots, with prickles and glandular hairs, at the ends of stems.

Flowers:

Sweet scented, 25-45 mm in diameter, on stalks(pedicels), 10-15 mm long with prickles or stiff glandular hairs.

Ovary - Short hairy styles up to 2 mm above orifice of disk. Ovule pendulous. Receptacle('hip') red, swollen, egg shaped, 15-20 mm long.

Sepals - 5, erect, green, overlapping, lance shaped, 3 outer sepals with deep, slender lobes, up to 15 mm long when in flower and enlarging when in fruit. Glandular hairs that are sometimes reddish on the back and along the edges. Persistent but free from the fruit.

Petals - 5, overlapping, pink to white petals, 8-22 mm long, longer than sepals.

Stamens - Many. Filaments 1.5-8 mm long.

Anthers - 1-1.5 mm long.

Fruit:

Enlarged flower base(torus or 'hip'), egg shaped to oblong, 10-25 mm long, orange to red. Hairless to glandular hairy and sometimes prickly near the base.

Seeds:

Many hairy, superior,1 seeded, yellow, irregular shaped, angled seeds(carpels) that are bony when ripe. Carpels, 2-7 mm long, enclosed within but free from the fleshy, berry-like hollow red torus or 'hip'.

Roots:

Shallow perennial rootstock with many, long laterals in the top 300 mm of soil.

Key Characters:

Wood, prickly shrubs.

Leaflets glandular beneath.

Stipules adnate to petiole.

Calyx single

Petals, 5.

Distinct floral tube which develops into a hollow succulent torus or receptacle

Carpels becoming achenes free within the torus.

From J.M. Black, N.T. Burbidge and E.M. Bennett.

Biology:

Life cycle:

Perennial. The plant reproduces from seed. Germination occurs at any time of year with a peak in autumn and spring. The young plants are relatively tender and can be grazed off by sheep (or rabbits). Plants do not normally flower until they are two or three years old. Flowering starts in late spring and continues into summer. The hips ripen in autumn and are held on the bushes into winter after the leaves have fallen. Some canes die each winter. New leaves and growth appear in spring. It suckers freely from the crown and individual plants may reach a considerable size with several hundred canes. Suckering is enhanced when slashing, burning, cultivation or some herbicides damage the plant.

Physiology:

Reproduction:

By seed and perennial rootstocks.

Flowering times:

Spring and summer in western NSW.

October to December in SA.

November to December in Perth with fruit from December to March.

Seed Biology and Germination:

Seed germinates at any time of year.

Seed remains viable in the sol for 3-4 years.

Vegetative Propagules:

Perennial rootstocks.

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Spread is mainly by seed via birds and animals that eat the fruit and pass the seeds. Some seed is also spread by water flows.

Produces large amounts of seed but few seedlings survive. Grazing with sheep (or rabbits) often kills seedlings.

In New Zealand it rapidly spread after control of rabbits.

Origin and History:

Europe. Western Asia. Northern India.

Probably in NSW by 1803.

Naturalised in Tasmania before 1838, SA by 1839 and Victoria by 1850. In Victoria it had covered 'large areas' by 1917.

Listed as the second most important weed of NSW in 1895.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC, WA.

Present in all parts of Tasmania. Locally heavy infestations of up to 1 ha or more are found in parts of the Midlands and the North.

Habitats:

More abundant in open situations with little competition.

Climate:

Temperate. Mediterranean. Humid and sub humid cool temperate areas.

Usually in areas with an annual rainfall of more than 600 mm.

Soil:

More abundant on well drained, calcareous soils of moderate to high fertility.

Rarely on sands or poorly drained areas.

Plant Associations:

Significance:

Beneficial:

Ornamental and hedge plant.

Young leaves and shoots eaten by stock but mature plants are protected by their prickly nature.

Honey plant producing much pollen.

The hips have a high vitamin C content and are sometimes collected and processed for human consumption. They contain 10-20 times more vitamin C than oranges or lemons.

Fruits can be eaten and young shoots candied. It has also been used in wines, sauces and jellies.

Used in herbal medicine for liver ailments, worms, baldness and snakebite.

Detrimental:

Weed of roadsides, range lands, streams, channel banks, pastures, old homesteads and disturbed areas.

Harbours vermin such as rabbits and restricts stock movements especially near watering points.

Contaminates hay with prickly stems.

Seldom a problem in improved pasture but occasionally competes with species suitable for grazing.

Toxicity:

Not recorded as toxic.

Legislation:

Noxious weed of ACT, NSW, SA, TAS, VIC.

Secondary Weed of Tasmania.

Management and Control:

Goats provide a method of non-chemical control. Infested areas are grazed with 7.5 goats per ha in the first year, then 1.25 goats per ha in subsequent years.

Slashing alone is generally ineffective.

Multiple cultivations provide control but may lead to erosion and soil structure problems.

Scalping to 30 cm and root raking can be effective but may require a follow up with other control measures to control re-shooting root and stem fragments and seedlings. Rehabilitation of the site is often required to prevent reinfestation.

Mechanical removal, or slashing and burning followed by cultivation, can provide control if repeated regularly and then followed by planting of competitive, preferably perennial, pastures species that is grazed.

Seedlings rarely establish in dense pasture or undisturbed native vegetation.

Improving pasture management usually prevents reinfestation.

Control with herbicides is usually the most cost effective. Metsulfuron (Brush Off®) and triclopyr (Garlon®) or triclopyr plus picloram (Grazon®) have provided the best results. Glyphosate can be used in home garden or other sensitive areas. Apply herbicides when the plant is actively growing and has good leaf area.

Basal bark applications using Access® plus diesel can be used where canes are removed mechanically.

Dead stems may be burnt or slashed in the following season to allow access and rehabilitation of the site.

Fire provides little control alone but assists access for herbicide application or other controls.

In Pine plantations hexazinone can be used.

Follow up treatments are essential for high levels of control.

Low volume spraying is usually effective providing the amount of active ingredient applied per bush is kept constant.

For high volume spraying use 1 litre of mix for each 2.5 cubic metres of bush (or 2.5 square metres of low lying Blackberry). This is equivalent to about 4000 L/ha of spray mix being applied.

In large infestations, consider using the cheaper metsulfuron for a year or two to reduce the size of the infestation then follow up with the more effective and costly triclopyr + picloram herbicides.

Thresholds:

Eradication strategies:

Mechanical control is difficult and most of the root system must be removed for effective control.

3 annual, summer applications of 1 L of Grazon® plus 250 mL of Pulse Penetrant® in 100 L of water generally gives very high levels of control. Replant native species after control has been achieved or establish a competitive, and preferably perennial, pasture species then graze to prevent seedlings establishing.

On large infestations, 10 g metsulfuron(600g/kg) plus 250 mL Pulse Penetrant in 100 L water, applied in summer when the plant is actively growing, provides a cheaper option to reduce the size of the infestation before Grazon® is used.

Herbicide resistance:

None reported.

Biological Control:

Bio control agents are under evaluation.

Related plants:

Cherokee rose (Rosa laevigata) has white flowers.

Dog Rose (Rosa canina) used as a rootstock for ornamental roses and has white flowers that may be fringed with pink.

Manetti or noisette rose (Rosa chinensis x moschata) has many petals.

Macartney Rose (Rosa bracteata) has white flowers.

Multiflora Rose (Rosa multiflora) is invasive in the USA.

Rambler rose (Rosa chinensis x multiflora) has pink flowers but the pedicels don't have prickles.

Rosa gallica

Plants of similar appearance:

See A key for weedy Blackberries and allied species in WA.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P216-217. Photos.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P397.

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P192-193. Diagram.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P345. Photo.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P209.

Hyde-Wyatt, B.H. and Morris, D.I. (1980) The Noxious and Secondary Weeds of Tasmania. (Tasmanian Department of Agriculture, Hobart, Tasmania). P54-55. Diagram.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #1066.4.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P209.

Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne). P572-575. Photos.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.