Other names:Gooseberry cucumber
Summary:A prostrate, running, annual herb or vine (to 4 metres) with slender rough stems. It has golf ball size striped, softly prickly melons arsing from yellow, 5 lobed flowers in summer. The green leaves, stems and fruit have a bitter taste and a strong smell when crushed.
First leaves:Oval to spade shaped, slightly lobed, edges toothed. Tip round. Notched where petiole joins blade. Hairy on edges and underneath.
Leaves:Alternate. Dark green to yellowish green. Simple undivided tendril below each leaf.
Stems:Green to yellowish green, slender, rough and prickly, vine up to 2000 mm. Branch near centre of plant. Pliable when young, brittle when old. Sometimes form extensive mats.
Flowers:Yellow to cream male and female flowers sometimes striped with green. Male flowers have yellow stamens in the centre, females don't. May be all male or all female plants or both may be on the same plant. Male flowers are on slender stalks (peduncle to 5 mm long, pedicel 3-8 mm long) in clusters of 2-4 in the leaf axils. Female flowers are single or a pair on stalks (pedicels) 3-8 mm long. Floral tube 3 mm long.
Fruit:Globular 20-30 mm diameter. Covered with long, soft, often hooked bristles. 5 lengthwise light and dark stripes, or mottles. Dark green initially and yellow on maturity. Flesh yellow-green and bitter. Borne on a slender curved stalk.
Seeds:Many, pale yellow, oblong to egg shaped, flattened, 3-4 mm long. Surface hairless.
Roots:Slender taproot with many, strong, shallow laterals.
Key Characters:Spined fruit slightly smaller than a golf ball. Strong smell when crushed.
Physiology:Fruit acts as an emetic.
Flowering times:November to March in SA.
Seed Biology and Germination:Vegetative Propagules:
Origin and History:South or eastern Africa.
Distribution:ACT, NSW, NT, QLD, SA, VIC, WA.
Soil:Common on sandy, alluvial, clay and loam soils and gilgai depressions or flats that are occasionally flooded.
Plant Associations:Prefers bare disturbed areas with summer moisture.
Detrimental:Weed of fallows, stubbles, pastures, roadsides, summer moist areas, firebreaks, water courses, stock yards and summer crops.
Toxicity:Horse, sheep and cattle losses have been associated with eating the melons. The smell of the plant makes it generally unpalatable and stock problems are not common. Most problems occur when feed is scarce.
Symptoms:Horses: Blindness, deafness, hind limb weakness.
Treatment:Remove stock from infested areas.
Legislation:Noxious weed of WA. (Pest plant in the Murray shire.)
Management and Control:Prevention of seed set by mechanical removal is feasible on small areas. Cultivation is effective but may lead to erosion problems. Herbicides are effective but need to be applied when the plants are young and not suffering water stress. Heavy grazing with wethers provides good control if feed is available to avoid problems with toxicity. This may be assisted by applying low rates of hormone herbicide to make the melons more palatable. Multiple germinations may occur over summer requiring repeated control measures. The use of residual herbicides such as Atrazine plus spray oil helps control subsequent germinations but may restrict the types or times of sowing of following crops. Triclopyr, metsulfuron and 2,4-D are commonly used for control.
Biological Control:Grazing with 24 wethers/ha for 2 weeks on a supplement of 150 g/head/day of Lupins or equivalent provides reasonable control of vegetative plants.
Related plants:West Indian Gherkin (Cucumis anguria)
Plants of similar appearance:Camel Melon is easily distinguished by its large fruit, branched tendrils and larger leaves that are usually a lighter green with more lobes and often with lighter coloured veins. In the cotyledon stage Camel Melon has a more obviously veined cotyledons than Prickly Paddymelon.
References:Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P159. Photo.
Acknowledgments:Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.