Solanum elaeagnifolium Invasiveness under Semi-Arid Environmental Conditions in Tunisia

Solanum elaeagnifolium, one of the world’s most widespread invasive weeds, thrives in the regions of Tunisia with a semi-arid climate. An enhanced understanding of its biological traits could be useful for its management. For this purpose, S. elaeagnifolium vegetative propagation, flowering, fruiting, and spread patterns were assessed under semi-arid environmental conditions at Chott Mariem (Tunisia) over three years (2013–2015). Our results revealed that S. elaeagnifolium showed an active vegetative growth phase during the spring (March–May). Thereafter, the plant stopped its vegetative growth in June–August in favor of flowering and fruiting. The vegetative growth resumed during September–October and declined in November, announcing its dormant period. Thanks to its vigorous rhizomatous system, S. elaeagnifolium was able to emit offshoots within a radius of 1.5 m from parent shoots by 30 months after its establishment. These findings could inform and improve dedicated management control options for S. elaeagnifolium. Silverleaf nightshade should be controlled before the full-flowering stage in spring and following the first autumnal rainfall to prevent vegetative propagation and fruiting.