Flag Iris

Iris germanica L.

Order: Liliales

Family: Iridaceae

Names:

Iris is from the Greek iris meaning rainbow and refers to the varied flowers colours.
Germanica
Flag Iris

Other Names:

Flag Lily
Fleur de Lis
German Iris.

Summary:

A stout, evergreen, rhizomatous plant with showy blue or white flowers with 3 erect petals and 3 bent backwards.

Description:

Cotyledons:

Two.

Leaves:

Shorter than the stem.
Stipules - None.
Petiole - None.
Blade - 30-50 mm long x 25-40 mm wide, sword shaped, folded lengthwise, joined along the edges and split at the base where it clasps the leaf on the other side of the stem.

Stems:

Flower stem (spathe) - large with oblong bracts with papery edges.

Flower head:

1-3 flowers on the end of the stalk (spathe).

Flowers:

Large, blue or white.
Ovary - Style has 3 branches that are winged on both sides. Wings end in an erect petal like lobe that have the stigma at the base and cover the anther opposite them.
Perianth - Tubular. Tube shorter than the 6 similar lobes. Lobes 70 mm long. The outer 3 lobes are bent back with a yellow beard running down the centre for about half their length. The inner 3 lobes erect and bent inwards.
Stamens - Equilateral.
Anthers - Parallel sided, attached at the base.

Fruit:

Egg shaped to oblong, 3 celled, angular capsule.

Seeds:

Globular or angular.

Roots:

Thick, long, horizontal rootstock.

Key Characters:

Leaves sword shaped.
2 or more flowers in each spathe.
Perianth segments united in a tube.
Inner perianth lobes large and erect.
Outer perianth segments yellow bearded.
Perianth tube to 25 mm long.
Style branches opposite anthers.
Style branches petaloid, ending in 2 erect crests or lobes, exceeding the stamens and stigmatic at the base.
From J.M. Black.

Biology:

Life cycle:

Perennial herb.

Physiology:

Reproduction:

By seed and rootstock fragments.

Flowering times:

September.

Seed Biology and Germination:

Vegetative Propagules:

Rootstock.

Hybrids:

Australian plants are probably a hybrid.

Allelopathy:

Population Dynamics and Dispersal:

Spread mainly by intentional garden planting.

Origin and History:

Europe. Eastern Mediterranean.
Introduced as a garden plant then naturalised in many parts of southern Australia.

Distribution:

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

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Temperate, Mediterranean.

Soil:

Plant Associations:

Significance:

Beneficial:

Ornamental flower.
Rhizome is known as orris in South Africa and used in toothpaste, face powder and perfume.

Detrimental:

Weed of disturbed areas.

Toxicity:

May cause gastroenteritis. No cases have been reported in Australia probably because they are unpalatable.
Acrid and irritates sensitive skin.

Symptoms:

Gastroenteritis

Legislation:

None.

Management and Control:

Avoid moving soil from infested areas.

Thresholds:

Eradication strategies:

Herbicides will probably provide the best control. Chlorsulfuron, metsulfuron and glyphosate are the most likely herbicides to provide control.
Hand removal not likely to be effective because the top tends to break off from the corms.

Herbicide resistance:

Biological Control:

Related plants:

Stinking Iris (Iris foetidissima)
Oriental Iris (Iris orientalis)
Winter Flowering Iris (Iris unguicularis)
Iris pseudacorus

Plants of similar appearance:

Cape Tulip has orange-pink flowers.
Daffodils and Jonquils have white to yellow flowers with 6 stamens rather than 3.
Freesia has larger flowers with a distinctive bend in the stem below the first flower.
Gladiolus has leafy floral bracts and the flowers tend to be on one side of the stem.
Ixia has 1 flower in each spathe and much narrower leaves.
Kangaroo Paws has broader leaves and red, black or green flowers shaped like kangaroo paws.
Montbretia (Crocosmia X crocosmiiflora) has stolons.
Patersonia has single 3 petal, purple flowers.
Snowflake has white flowers with 6 stamens rather than 3.
Sparaxis has two tiny lobes on the style branches.
Watsonias and African Cornflag are much larger.

References:

Black, J.M. (1978). Flora of South Australia. (Government Printer, Adelaide, South Australia). P374. Diagram.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P376-377.

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). P34.

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #683.2.

Acknowledgments:

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