Habitat in Merimbula (Jackie Miles)

Typical roadside habitat (Jackie Miles)

Plant with flowers (Jackie Miles)

Flower (Tomasz Kurzawa)

Leaf with extrafloral nectaries on petiole (stem) (Tomasz Kurzawa)

Flower with shallow lower sepal and narrow spur (Tomasz Kurzawa)

Side view of flower showing spur (Tomasz Kurzawa)

Swollen fruit (Jackie Miles)

Scientific Name

Impatiens walleriana

Common Name

garden balsam, Impatiens, busy Lizzie

Synonyms

I. wallerana, I. holstii, I. sultani

Family

Balsaminaceae

Origin

Native to East Africa

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Habit

Glabrous (hairless), perennial (life span extends over more than 1 season) herb to 1 m high, stems are more or less succulent. Fruits are "explosive".

Habitat

Grows in bushland, along water courses and around habitation on the North and Central coast  of NSW. It has also been found at a couple of locations on moist, shaded road verges in Merimbula, moist remnant bush on drainage lines and around shady wetland margins in Dalmeny and Batemans Bay, NSW South Coast. In Queensland the plant is naturalised on basalt soils in Palmerston National Park. It colonises forest margins and is displacing native fern communities around waterfalls. It has also naturalised in riparian habitats and other moist areas in South East Queensland. Its brittle stems are easily broken and carried downstream by floodwaters. It is used as an ornamental in Australia.

General Description

Stems and Leaves:

The young stems are greenish or reddish and translucent, mature slightly thickened and woody at the base. The stems can branch vigorously. The leaves are spirally arranged, glabrous (without hairs or scales), somewhat fleshy, broadly elliptical or ovate to oblong-elliptical or oblong-ovate, 4-13 cm long and 2.5 -5.5 cm wide, with 5-8 pairs of lateral veins and 1-2 (sometimes more) extrafloral nectaries (glands outside the flower) along the petiole (leaf stalk). Leaf margins coarsely toothed.

Flowers and Fruit:

The flowers appear predominantly in pairs or threes at the leaf-stem junction in the top part of the plant. They may be in different shades of pink, rose or red, sometimes also white, 5 petalled, about 3 cm in diameter. Upper petal crested, lateral petals fused towards base. Flower stalks 3-5 cm long. Lateral sepals 2, small, green, 3-7 mm long. Lower sepal whitish, shallow, abruptly constricted into 3-5 cm long narrow spur. The flowers appear  throughout the year. The fruit is a smooth greenish capsule, 15-20 mm long and 4-6 mm wide, swollen in the middle. Ripe fruits explode with even slight push and eject small brownish seeds.

 

Distinguishing Characteristics

It can be distinguished from poor man’s  Rhododendron Impatiens sodenii in that I. walleriana is a lower plant, has smaller  flowers in different shades of pink, rose or red, branched stems and leaves spirally arranged. Whereas I. sodenii plant is more than 1 m high, flowers are bigger, most often pale pink or white, stems simple or only moderately branched and leaves in dense whorls 6-12 rather congested towards stem top.

I. niamniamensis, recently found occasionally naturalising close to where it is cultivated in New Zealand, has striking red-yellow-green flowers and saccate (pouch shaped) lower sepal with upright spur.

Policeman’s helmet I. glandulifera, Kashmir balsam I. balfourii and I. balsamina are annual plants with a saccate (pouch shaped) lower sepal.

 

Sources & References

Grey -Wilson C (1980) ‘Impatiens of Africa.’ A. A. Balkema, Rotterdam

Csurhes S. & Edwards R. (1998) 'Potential Environmental Weeds Candidate Species for Preventative Control. National Weeds Program', Queensland Department of Natural Resources.

Heenan P. B., de Lange P. J., Cameron E. K., Ogle C. C. & Champion P. D. 2004. Checklist of dicotyledons, gymnosperms,  and pteridophytes naturalised or casual in New Zealand: additional records 2001-2003. New Zealand J. Bot. 42: 797-814.

Prepared by: Wojciech Adamowski, January 2006

Checked by: Jackie Miles, February 2006

 

Website references:

http://www.sydneyweeds.org.au/

Flora of New South Wales  http://plantnet.rbgsyd.nsw.gov.au/

 

 

 

 

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