A blue flowered, 4 petalled, erect annual herb with toothed to lobed leaves and long pods with a conical beak held away from the stem. Pods tend to break into short segments enclosing a single seed when ripe.
Description:
Cotyledons:
Two. Oval. Tip indented. Sides convex. Base tapered. Hairless. Petiole longer than blade.
First leaves:
Oval. Tip round. Edges slightly toothed to lobed. Base tapered to squarish. Small hairs on upper and lower surface. Petiole as long or longer than blade and hairy.
Leaves:
Form a rosette.
Stipules -
Petiole - Shorter than blade.
Blade - Oval. Tip rounded to pointed. Sides toothed, scalloped or lobed. Base tapered. Surface warty.
Stem leaves - Oval to spear shaped. Edges toothed. Tip round. Scattered hairs on both surfaces.
Stems:
Flower stem - Erect, branched, up to 600 mm tall.
Flower head:
Single flowers alternating up the stem.
Flowers:
Blue with 4 petals
Ovary -
Sepals -
Petals - 4. Blue.
Stamens -
Anthers -
Fruit:
Long, thin, usually curved pod 15-50 mm long (including the beak) by 1-2 mm wide with a 5-15 mm long seedless beak. Pod breaks crosswise into 1 seeded segments about 1.5 mm long by 2 mm diameter. Pods held away from the stem on a short 2-3 mm long stalk (peduncle).
Seeds:
Grey to blue-black. Enclosed in pod segments that are 1-2 mm long by 1-2 mm diameter, ribbed on one side and pitted on the other.
Roots:
Taproot
Key Characters:
Blue flowers.
Biology:
Life cycle:
Annual herb.
Physiology:
Reproduction:
By seed.
Flowering times:
Seed Biology and Germination:
Vegetative Propagules:
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
Spread by seed.
Origin and History:
Eastern Europe and Asia.
Distribution:
VIC.
Habitats:
Climate:
Temperate.
Soil:
Plant Associations:
Significance:
Beneficial:
Detrimental:
Weed of crops.
Toxicity:
Symptoms:
Treatment:
Legislation:
None.
Management and Control:
Thresholds:
Eradication strategies:
Spray small areas with a mixture of 0.5 g Eclipse® plus 10 mL Brodal® in 10 L water. Remove and burn plants carrying seed. Repeat annually after seedlings appear.
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:
None in the same genus.
The native Brassicaceae species usually have short, broad and smooth pods.
Plants of similar appearance:
Hedge Mustard (Sisymbrium officinale) has the pods held close to the stem.
References:
Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).
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.
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). #241.1.
Moerkerk, M.R. and Barnett, A.G. (1998). More Crop Weeds. R.G. and F.J. Richardson, Melbourne. P66. Diagrams. Photos.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.