* two - This is a number, not an adjective.
* large - This describes the oaks, so it is an adjective.
* oaks - This is a noun, not an adjective.
* covered - This is a verb, not an adjective.
* your - This is a possessive pronoun, not an adjective.
* evergreens - This is a noun, not an adjective.
Therefore, there is one adjective in the sentence: large.