The study of various periodic behaviours of plant species or the phenology has great significance because it not only provides knowledge about the plant growth pattern but also provides the inferences on the effect of environment and selective pressure on flowering and fruiting behaviour. In this paper an attempt has been made to record such data regarding periods of leaf fall, leaf flushing, flowering, fruiting and all. This was done for a period of three years for two species viz. Picrorhiza kurroa and Saussurea costus of course which were somehow having medicinal properties. In the study the leaf fall peak period was found in last part of December, leaf flushing peak period in the month of march where as flowering and fruiting activity peak period was found during the month of April- May and July-August respectively. So, this type of study will be helpful to give inferences in future whether the of climate change are giving pressure on the periodic behaviour of plant species.