Over 50% of the Bulgarian flora is represented there with a big number of endemic, relict, rare and threatened Red Book species.

The Strandja Rhododendron (Rhododendron ponticum), flowering with fabulously beautiful violet flowers, is a symbol of the Park.The centuries-old natural Strandja forest hides Tertiary relicts and local endemic plant species that can be seen only here.

The relict plant community and individual plants have remained since the Tertiary Age (about 70 million years ago). The total numbers of plant species in Strandja is about 1,665