Studies were conducted at three locations viz., Research Farm of Department of Agronomy Palampur, Research Farm of Regional research Station, Dhaulakuan and Research Farm of Regional Research Station, Bajaura, of Himachal Pradesh Krishi Vishvavidyalya, Palampur during 1987–88 to study the ecology of Oxalis latifolia H. B. & K and Ageratum conyzoides L. The growth of Oxalis latifolia was more in terms of shoot height, number of leaves per plant and number of bulbs per plant at Dhaulakuan under sub-montane sub-tropical low hills zone and slow growth was at Palampur (sub-temperate humid mid hill zone) and Bajaura (sub-temperate mid hill zone). Flowsring was noticed during November-December at Dhaulakuan and during July-August at Palampur and Bajaura. The population of Ageratum conyzoides which higher at Palampur (subtemperate humid mid hill zone) as compared to Dhaulakuan. Flowering was noticed during March-April at Dhaulakuan and during August-September at Palampur
