Micro climatic fluctuations coupled with edaphic, topographic and biotic factors have endowed this sanctuary with rich floral diversity.

The natural vegetation growing in this sanctuary has been classified into following types:

In addition, this sanctuary harbours three minor vegetation types of which two are man-made. They are:

• Low altitude marshy grass lands known locally as vayals
• Teak plantations
• Eucalyptus plantations

The evergreen and moist deciduous forests are the most important natural vegetation types.  Sholas are confined to small areas in the hilltops of Karimala Gopuram and in the foothills of Pandaravara peak which is known by the name Karian Shola.