We conducted a greenhouse study to examine the effects of different habitat conditions and environmental resources on the growth rates of crimson fountaingrass, an invasive, alien, perennial grass in South Africa. To help understand the factors promoting the spread of this emergent alien grass, we investigated the effects of temperature regimes, nutrient and moisture addition, and soil type on seedling growth rates and biomass allocation. Our results suggest that crimson fountaingrass seedlings do not tolerate drought because they died within 1 mo without water. Additional nutrients and extra water increased seedling growth rates throughout the study period. Higher temperatures with extra moisture increased seedling growth rates and the development of belowground biomass throughout the study period. This study demonstrates the importance of available environmental resources and their interaction with some habitat conditions in promoting crimson fountaingrass growth. We suggest that soil moisture and nutrient availability are critical factors affecting successful establishment of crimson fountaingrass in arid environments. Managers should target seedlings for removal following precipitation and in areas of nutrient enrichment, such as near rivers and at road–river crossings.

Nomenclature: Crimson fountaingrass, Pennisetum setaceum (Forsk.) Chiov. PESSA