Silver-leaf nightshade (Solanum elaeagnifolium) is a deep-rooted summer-growing perennial plant from the tomato family Solanaceae. It is an erect, bushy plant growing, 30 to 80 cm high. It reproduces by seed and from creeping perennial roots. Growth above ground from existing root systems appears in October or November. Plants flower from November or December to April and fruit is commonly set in February. Plants die back before winter but the dead stems with berries usually remain standing for a few months. The seeds germinate in autumn and the young plants produce an extensive root system in their first few months.
- Stems – Erect, branched, densely covered in fine hairs and with numerous slender orange prickles.
- Leaves – Silvery white underside due to dense cover of minute white hairs, alternate, 2.5 to 10 cm long, 1 to 2 cm wide, margins often scalloped; often with orange prickles on the veins.
- Flowers – Usually purple to violet, occasionally white, commonly 2.5 cm in diameter but up to 4.0 cm diameter with five fused petals forming a shallow tube and five yellow anthers.
- Fruit – A smooth globular berry about 1.0 to 1.5 cm diameter, green with dark striations when immature and yellow and orange mottled and becoming wrinkled when ripe. There can be up to 60 per plant.
Controlling Silver-leaf Nightshade
Silver-leaf Nightshade is a weed of national significance and is identified as being invasive, having the potential for widespread environmental, social and economical damage. Landowner’s and land managers at all levels are responsible for actively managing this weed.
Silver-leaf nightshade is very difficult to kill. Plants can be spread by seed or root pieces. It is best to try and treat isolated plants and small patches as they appear. Extended and integrated control measures are vital to manage this weed.
Silver-leaf nightshade is toxic to animals, with cattle more susceptible than sheep. Good ground cover and competitive pastures such as lucerne can be a key element in controlling the spread of the plant. The control strategy must aim to prevent berry-set at the early flowering stage as viable seeds can be found in young, green berries as small as 7 mm in diameter.
Treating isolated patches
Repeated spot spraying with Starane™ Advanced Herbicide over several seasons will eventually control small areas of silver-leaf nightshade and ensure grass pastures can recover to compete with new germinations.
Treating extensive infestations
Starane Advanced at 600 mL/ha is the best option for broadcast application on silver-leaf nightshade to greatly reduce plant numbers as well as being selective to grass pastures. Use of glyphosate Herbicide should only be considered in fallow situations prior to planting crops or new pastures.
Perennial pastures provide ground cover and compete against silver-leaf nightshade, with phalaris-based pastures being the most competitive because of the amount of residue remaining over summer.
Herbicides for Control of Silver-leaf nightshade
#Note: Preferred product option in bold. *Consult label for details of growth stage and use, especially where range of rates is given.