Cardamine hirsuta L.
Cardamine is the Greek word for a cress like herb.
Common Bittercress refers to its bitter taste and association with the cress or mustard group of plants.
Other Names:Flickweed because the pods flick the seeds out when ripe.
Hoary Wood Cress.
Summary:Erect, slender, small, annual, herb, branching from the base and usually hairless except at the base. Up to 300 mm tall. The leaves have 1-7 leaflets. The side leaflets are somewhat circular and the terminal leaflet is kidney shaped. It has small, white 4 petalled flowers at any time of the year that form pods up to 25 mm long that flick the seeds out when ripe.
Two. Lie against the root (accumbent).
Leaves:Many basal leaves in a rosette.
Petiole - With a few hairs at the base or on the edges.
Blade - Usually less than 100 mm long. Compound with 3-7 leaflets on either side of the midrib. Leaflets lobed, angled or smooth on the edges. Several pairs of circular to lance shaped side leaflets and a kidney shaped end leaflet, but sometimes reduced to the single terminal leaflet. Leaflets on small stalks. May have a few long, simple, straight hairs on the upper surfaces of leaflets especially near the edges. Tip rounded. Base squarish.
Stem leaves - Alternate, few and becoming smaller up the stem.
Stems:300 mm tall. Branch from base. Slender, smooth and hairless.
Flower head:Raceme, usually many flowered.
Stigma - sessile or almost sessile.
Sepals - 1.5-3 mm long. Green purple with a white margin. Spreading.
Petals - 4. White. 2.5-5 mm long, clawed. Longer than sepals.
Stamens - Usually 4 and sometimes 6. Nectary glands.
Fruit:Erect pods. Extend well below the flowers. Parallel sided. 15-20 mm long x 1-1.5 mm wide. Flattened. On spreading stalks, 5-25 mm long x 1-1.5 mm wide. The side of the pod curls spirally up from the base to release the seed explosively.
Seeds:Flattened. Smooth. In 1 row in the pod.
Key Characters:Plant branched only from the base. Hairless, smooth stem. Basal leaves in a rosette.
Annual. Flowers in September.
Flowering times:Most of the year.
September in WA.
Seed Biology and Germination:Vegetative Propagules:
Hybrids:There are a number of similar species of unknown identity.
Allelopathy:Population Dynamics and Dispersal:
Origin and History:
Northern hemisphere temperate regions. Cosmopolitan.
Distribution:ACT, NSW, NT, QLD, SA, TAS, VIC, WA.
Not in NT according to Auld.
Courtesy Australia's Virtual Herbarium.
Habitats:Cool and damp areas.
Common in gardens, nurseries and pot plants.
Weed of gardens, nurseries and glasshouses.
Toxicity:Not recorded as toxic.
Management and Control:Thresholds:
Manually remove isolated plants.
Prevent seed set. Spray small infested areas with 10 g/ha Eclipse® plus 500mL/ha of Brodal® plus 1% spray oil in winter each year.
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 under-grazed, 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 Brassicaceae species though Wild Radish tends to regrow.
Herbicide resistance:Biological Control:
Flax-leaf Alyssum (Alyssum linifolium)
Wall Cress (Arabidopsis thaliana)
Black Mustard (Brassica nigra)
Broccoli (Brassica oleracea var. italica)
Brussels Sprouts (Brassica oleracea var. gemmifera)
Cabbage (Brassica oleracea var. capitata)
Cauliflower (Brassica oleracea var. botrytis)
Chinese Cabbage (Brassica chinensis)
Indian Mustard (Brassica juncea)
Kale (Brassica oleracea var. acephala)
Kohlrabi (Brassica oleracea var. gongylodes)
Mediterranean Turnip (Brassica tournefortii)
Rape or Canola (Brassica napus var. napus)
Rapeseed (Brassica rapa var. sylvestris)
Savoy cabbage (Brassica oleracea var. sabauda)
Smooth Stemmed Turnip (Brassica barrelieri subsp. oxyrrhina was Brassica oxyrrhina)
Swede (Brassica napus var. napobrassica)
Turnip (Brassica rapa var. rapa)
Twiggy Turnip (Brassica fruticulosa)
Winter Rape (Brassica napus var. biennis)
Sea Rocket (Cakile maritima)
White Ball Mustard (Calepina irregularis)
Shepherd's Purse (Capsella bursa-pastoris)
Common Bittercress (Cardamine hirsuta)
Wood Bittercress (Cardamine flexuosa) is not in WA.
Ward's Weed (Carrichtera annua)
Wall Rocket (Diplotaxis muralis)
Sand Rocket (Diplotaxis tenuifolia)
Oval Purse (Hornungia procumbens was Hymenobolus procumbens)
Argentine Peppercress (Lepidium bonariense) is often found around granite rocks.
Common Peppercress (Lepidium africanum) is common in WA.
Field Cress (Lepidium campestre) has clasping stem leaves.
Garden Cress (Lepidium sativa)
Hoary Cress (Lepidium draba was Cardaria draba)
Lesser Swinecress (Lepidium didymum was Coronopus didymus)
Matted Peppercress (Lepidium pubescens)
Perennial Peppercress (Lepidium latifolium)
Virginian Peppercress (Lepidium virginicum)
Sweet Alyssum (Lobularia maritima)
Common Stock (Matthiola incana)
Night-scented Stock (Matthiola longipetala)
Muskweed (Myagrum perfoliatum) is not in WA.
Ball mustard (Neslia paniculata)
Cultivated Radish (Raphanus sativus).
Sea Radish (Raphanus maritimus).
Turnip Weed (Rapistrum rugosum)
Watercress (Rorippa nasturtium-aquaticum)
White Mustard (Sinapis alba) has white seed.
Charlock (Sinapis arvensis)
Sisymbrium altissimum is not in WA.
Smooth Mustard (Sisymbrium erysimoides)
London Rocket (Sisymbrium irio)
Hedge Mustard (Sisymbrium officinale)
Indian Hedge Mustard (Sisymbrium orientale)0
African Turnip Weed (Sisymbrium thellungii) is not in WA.
Succowia balearica is in Kings Park in Perth.
Plants of similar appearance:Cardamine flexuosa is often perennial and has 6 stamens whereas Common bittercress usually has 4 and only occasionally 6.
Cardamine paucijuga is a native species.
The native Brassicaceae species usually have short, broad and smooth pods.
References:Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P132.
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P372. Diagram.
Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P184. 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). #249.2.
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). P163.
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