White Mustard

Sinapis alba L.

Synonyms -

Family: - Brassicaceae


Sinapis is from the Greek sinapi meaning mustard.

Alba means white and refers to the pale colour of the seeds.

White Mustard because it has white seeds and is in the Mustard family

Other Names:



A hairless or sparsely bristly winter annual with leaves that are deeply lobed or with leaflets. It has 4-petalled, yellow flowers in spring that form 10-25 mm long pods with a 10-20 mm long, flat sabre-like beak. There are 2-8, white, spherical seeds in each pod.



Two. Heart shaped. Tip indented. Edges smooth. Base squarish. Hairy on the lower surface and edges. Petiole loner than the blade, red and hairy. Young stem red to purple.

First leaves:

Oval. Tip rounded. Deeply undulating edges. Wrinkled surface with prominent veins. Hairy.


Stipules -

Petiole - Shorter than leaf blade on lower leaves, very short on upper leaves.

Blade - Oval in outline, to 150 mm long. 2-6 deep lobes with a large, oval end lobe or divided into leaflets with a larger terminal leaflet. Lobes( or leaflets) have teeth or are lobed also. Tip round to pointed. Base squarish and may be tapered on the leaflets. Usually roughly hairy.

Stem leaves - Smaller with a shorter petiole.


Flower stem - Erect, 300-800 mm tall. May have stiff hairs.

Flower head:

Dense panicle like raceme that lengthens as the fruits mature. Flowers alternate.


Yellow, 4 petals, 12-15 mm diameter.

Ovary -

Sepals - Spreading. Half as long as the petals, 5-7.5 mm long.

Petals - 4. Yellow, 10-15 mm long.

Stamens -

Anthers -


20-40 mm long (including the beak) by 3-4 mm diameter, 2 celled, cylindrical pod with 3-5 veins. Constricted between the 2-8 seeds. Beak curved, conical and flattened (flat sword shaped), 10-30 mm long, bristly and with one or no seed. Pod and beak usually covered in stiff hairs. Pods on stout, stalks, 8-13 mm long, that are almost at right angles to the stem.

1-4 seeds in each cell in a single row. J.Black


Pale yellow brown, dull, spherical, 1.7-2.3 mm diameter. Surface with a slightly frosted appearance and hairless. Pungent taste. Tip round. Edges round and smooth. Base round.



Key Characters:

Siliquas hispid with a flattened beak, not appressed to the stem, more than 3 time as long as broad, cylindrical and constricted between the seeds.

Beak seedless.

Septum of fruit broad,

1-4 seeded in each valve.

Valves 3-5 nerved.

Fruit dehiscent, the seeds released by the falling valves.

Seeds spherical.

Adapted from Nancy Burbidge


Life cycle:

Annual. Seeds germinate from autumn to spring and develop a rosette of leaves. The flowering stem emerges in spring and plants die soon after seeding with the onset of high temperatures and summer drought.



By seed.

Flowering times:

Spring in Western NSW.

Seed Biology and Germination:

Vegetative Propagules:



Population Dynamics and Dispersal:

Spread by seed and intentional plantings.

Origin and History:

Mediterranean, Western Asia and Europe.





Temperate to sub tropical.


Plant Associations:



Fodder but may be toxic.

Sown for the seeds to make mustard powder and the edible leaves that are used as a salad vegetable. Prepared mustard is a mixture of the ground seeds of White Mustard (Sinapis alba), Black Mustard (Brassica nigra) and starch and is used as an emetic and in mustard plasters


Weed of crops, roadsides.


Cattle may be poisoned by the stubble of White Mustard crops or pods and seeds in feed meals though field cases in Australia are rare.

Oil of White Mustard can cause blistering and ulceration of the skin, burning of the tissues, heart stimulation, loss of consciousness and death. It can also induce eczema and urticaria.





Management and Control:

Normal grazing usually provides reasonable control. Heavy infestations or stubbles may cause stock illness. Spraying with 2,4-D amine or Tigrex® is cheap and reasonably effective.


Eradication strategies:

Manually remove isolated plants and spray the area each winter with 500 mL/ha of Brodal.

Buy grain and produce from White Mustard free areas.

Most of the Brassicaceae weeds have dormant seeds that continue to germinate throughout the season and for several years. They often mature and set seed very quickly. Manual removal is effective but must be done at least every 8-10 weeks. Once pods are formed, seed will often mature even if the plant has been uprooted. Soil disturbance often leads to a flush of seedlings.

Many are somewhat unpalatable, so grazing only offers partial control. They often flourish in undergrazed, sunny areas.

In bushland situations, fairly selective control can be achieved with 100 mL spray oil plus 0.1 g Eclipse® or 0.5 g Logran® in 10 L water. 5 mL Brodal® is often added to this mix to provide residual control of seedlings. Spray the plants until just wet from the seedling stage up to pod formation.

Isolated plants should be removed manually and burnt if flowering or seeding and a 10 m buffer area sprayed with 10 mL Brodal® in 10 L water.

500 mL/ha of glyphosate(450g/L) can be used at flowering to reduce the seed set of most species on roadsides without causing significant damage to most native plants.

Wick application with 1 part glyphosate(450g/L) in 2 parts water or overall spraying with 100 mL glyphosate(450g/L) in 10 L water provides reasonable control of most species though Wild Radish tends to regrow.

Herbicide resistance:

None reported.

Biological Control:

Related plants:

Charlock (Sinapis arvensis) does not have petioles on the simple or toothed upper leaves and 8 or more red brown seeds in a pod with a conical beak that is shorter than the pod.

Plants of similar appearance:

Wild Radish, Radish, Turnips and Mustards


Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P181

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P332. Photo.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume . P. Diagram.

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). P120.

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

Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #930.1.

Moerkerk, M.R. and Barnett, A.G. (1998). More Crop Weeds. R.G. and F.J. Richardson, Melbourne. P73. Diagrams. Photos.


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