The flora is very diverse for the size of the island.

The prevailing plants are cedar, juniper, mastic tree, either in the form of shrubs or a trees, as well as ammophilous vegetation.  The roots of the cedar are at least double in size of their hight.  Apart from the long roots, they also have a lot of very thin ones which form a dense net holding the sand. 

Chrissi has a fantastic cedar forest which is unique in Europe. It is 350 hectares in size and has approximately 14 trees per hectare. The average age of the trees is 200-300 years and the forest covers about a quarter of the island.  These trees are a rare variety of Lebanese cedar. They grow up to 10 metres high and the diameter of their trunk is up to 1 metre. 

Compared to its size, Chrissi has a very large number of plant species which correspond to one twentieth of the Cretan flora.  There are more than 100 recorded species.  13 are endemic to Greece, five of them are endemic to Crete and one is endemic to Chrissi, which means that it cannot be found anywhere else in the world.  It is a type of colchicum called Colchicum Costurieri.