Narrow-leaved Lupin

Lupinus angustifolius L.

Family: - Fabaceae.


Lupinus is from the Latin word for wolf and applied because they prey on the soil and inhabit poor soil types.

Narrow-leaved Lupin because the leaflets are narrower than in other species.

Other names:

Blue Lupin


New Zealand Blue Lupin.


Narrow-leaved Lupin is an erect, robust, much branched annual herb or shrub with 5-9, narrow, finger-like leaflets, 1-6 mm wide, radiating from a central point. The flowers are arranged alternately and almost whorled near the top of the tall flower spike. The dark blue pea-type flowers are 10-15 mm long. The seed pods are 35-60 mm long, slightly flattened and sometimes a little constricted between the 2-6 seeds. The seed is smooth and mottled.

Native to the Mediterranean region, it is a common weed of roadsides and waste places, sometimes invading bushland and flowering in spring.



Two. Fleshy, shiny, oval to kidney shaped, thick, tip round, base tapered, edges smooth and undulating, Surface somewhat dimpled and undulating. Short petiole. Hairless.

Short hairs on stem below the cotyledons.

First leaves:

Similar to later leaves.


5-9 leaflets arranged like fingers on a hand.

Stipules - Parallel sided, joined to base of petiole.

Petiole - Long and slender. Hairy.

Blade - Of leaflet, dark green, 10-50 mm long by 1-6 mm wide, oblong, long and narrow. Pointed or rounded tip. Tapered base. Hairless on the upper surface, low lying hairs underneath and on the edges.


Single stem with many branches below the flower spikes, round, 200-1500 mm high. Short fine hairs.

Flower head:

50-200 mm long, almost stalkless, spikes at the end of the main stem or in upper leaf axils (Terminal and axillary). Flowers alternate and are spaced in the lower section grading to almost in rings near the top.


Deep blue tinged with purple, rarely pale blue, pink, purple, cropped varieties are commonly white. Not scented. On 2-4 mm long stalks (pedicels).

Bracts - Short, oblong.

Ovary - Sessile. Style hairless, incurved. Stigma terminal.

Calyx - 7-8 mm long, hairy. Tube 2-3 mm long. Upper lip 3-4 mm long and divided into 2 acute tipped lobes. Lower lip 6 mm long with 3 short lobes (or rarely without lobes).

Petals - Blue, white, pale pink or purple. Standard, 11-15 mm long with an egg shaped limb. Wings 11-15 mm long. Keel 10-14 mm long, slightly shorter than the wings, tip is dark and acute.

Stamens - United in a tube.

Anthers -


Flattish pods 35-60 mm long by 8-16 mm wide. Hairy. Tip pointed or beaked. 2-6 seeds per pod.


Seeds grey-brown with brown marbling or whitish spots, rarely white brown or black, smooth, globular, 6-8 mm long by 5-6 mm wide. Tip smooth, Edges smooth and convex. Base round to slightly pointed.


Strong taproot. Nitrogen fixing nodules on roots and especially at the top of the taproot. Top of taproot and nodules are red when cut if the plant is growing.

Key Characters:

5-9 leaflets, 1-6 mm wide.

Racemes almost sessile.

Lower flowers alternate.

Upper calyx lip deeply divided into 2 lobes.


Life cycle:

Annual. Seed germinates in autumn to winter. It grows through winter and flowers from August to November. The plant dies with the onset of summer drought.


Fixes nitrogen.


By seed.

Flowering times:

August to November in Perth.

Spring in WA.

Seed Biology and Germination:

Little dormancy.

Vegetative Propagules:




Population Dynamics and Dispersal:

Spread mainly by intentional planting.

Origin and History:

Southern Europe. Mediterranean.





Temperate. Mediterranean.


Most abundant on sandy soils.

Plant Associations:



Rotational legume crop.

Seed used for high protein fodder.



Weed of crops, roadsides, wood lands and disturbed areas.


Three types of toxicity;

1) Lupinosis due to phomopsin produced by an associated fungus, Phomopsis leptostromiformis and results in liver damage. It occurs when stubbles or hay are grazed and may result in heavy stock losses.

2 ) Lupine poisoning is due to alkaloids in the plant and especially the seeds. It occurs when large quantities of the seed are consumed. Cattle sometimes suddenly die after eating green pods.

3) Some species in North America cause birth defects in cattle but this has not been recorded in Australia.


Lupine poisoning symptoms are usually seen after driving and include, frothing at the mouth, falling on one side, teeth grinding, laboured breathing and convulsions. If left to rest they usually recover.

Lupinosis symptoms include lethargy, loss of appetite and condition, jaundice, photo sensitisation, loss or directional sense and death. Once symptoms are evident they rarely make a full recovery and may linger for months before death.


Grow new varieties that are phomopsis resistant.

Remove stock from lupin areas. Avoid grazing stubbles or feeding large quantities of seed.

No economic treatment of afflicted animals.



Management and Control:

Seedlings are susceptible to cultivation and grazing. Germinations may occur after planting crops and a number of selective herbicides provide good control.


1 plant/m2 is usually worth controlling in cereals to reduce contamination of grain.

Eradication strategies:

Prevent seed set for 3-4 years by mowing, grazing, cultivating, spraying or hand pulling before flowering.

Small areas can be treated with 20 mL of Tordon®75-D in 10 L of water in early winter. This will kill existing plants and leave a soil residual which controls Lupin and other broad-leaved seedlings for about a year. Larger areas can be treated with more selective herbicides such as 200 g/ha Lontrel®750 or 50 g/ha Logran®. The latter two treatments are relatively selective in bushland. For hand spraying mix 25 mL wetting agent plus 4 g Lontrel®750 or 1 g Logran® in 10 L of water. Metsulfuron(600g/kg) at 10 g/ha provides good control but is less selective. Glyphosate is relatively ineffective. Grazing by native animals usually keeps Lupins under control in healthy bushland.

Herbicide resistance:

Biological Control:

Related plants:

Pearl Lupin (Lupinus mutabilis)

Sandplain Lupin (Lupinus cosentinii)

Tree Lupin (Lupinus arboreus)

White Lupin (Lupinus albus) has wider leaflets that are widest in the upper half or near the middle.

Yellow Lupin (Lupinus luteus)

Lupinus hirsutus

Lupinus pilosus

Lupinus polyphyllus cv. Russell hybrid is naturalised in NSW, Victoria and New Zealand and has long sprays of brightly coloured flowers.

Plants of similar appearance:


Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P468.

Gardner, G.A. and Bennetts, H.W. (1956). The toxic plants of Western Australia. (West Australian Newspapers Ltd, Perth). p???99-102.

Gilbey, D. (1989). Identification of weeds in cereal and legume crops. Bulletin 4107. (Western Australian Department of Agriculture , Perth). P39. Photos.

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). P152.

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). #768.2.

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). P281.

Moerkerk, M.R. and Barnett, A.G. (1998). More Crop Weeds. R.G. and F.J. Richardson, Melbourne. P85. Diagrams. Photos.


Collated by HerbiGuide. Phone 08 98444064 or for more information.