A study was undertaken in Biligiri Rangan hills Temple wildlife sanctuary, Karnataka covering an area of 540 km2 by laying 134 plots measuring 80 m × 5 m at 2-km intervals over the sanctuary, to understand the influence of two weeds, Lantana camara and Chromelina odorata, on species richness and stem density. All stems above 1 cm DBH were enumerated. Plots were classified based on the presence and absence of Lantana and Chromelina. Species richness and stem density were high in the plots infested with Lantana compared to control and lower species richness was recorded in plots infested with Chromelina compared to Lantana. It is argued that Lantana may not suppress the growth of other species; it probably grows in the plots with more moisture, preferred by many other species.