One might expect an area so densely populated to be poor in flora: on the contrary, the San Bartolo National Park has many pleasant surprises in store for its visitors. A recent study of the “vascular flora” present in the protected area has shown that rare species are to be found throughout the region, with especially interesting species on the cliffs. On the cliffs above Baia Flaminia, for example, is found a very rare plant which goes by the name of “maritime flax”; this is the only area in the entire region where it grows. Equally significant are rushes (Juncus subnodulosus), and the rock carrot (Daucus giungidum), which can be found only in a very few other places on the coast of Le Marche. On the most rocky slopes, the small reed Arundo plinii is the plant most commonly found, while on drier and more stable terrain Spanish broom (Spartium junceum) grows in quantity, its bright yellow flowers scenting the air and making an unforgettable contrast with the brilliant blue sky and the blue-green sea.

The presence of several conifer species is to be referred to the historical settlements relative to the renaissance villas: stone pine (Pinus pinea), cluster pine (Pinus pineaster), Cypress (Cupressus sempervirens and C. Lusitanica), and the presence of the holm-oak (Quercus ilex) and laurustine (Viburnum tinus). Successive reforestation in the 1960s added sycamore maple (Acer Pseudoplatanus), Aleppo pine, black pine (Pinus nigra), Siberian elm (Ulmus Laevis) and other allochthonous species to the Park flora. As for the rest, the vegetation of the landscape is that typical of an agricultural environment, intensely cultivated until the 1950s, where the arboreal species are represented by olive, fig, cherry, mulberry, sorb, almond, with the presence of rows and isolated exemplars of large elders, which are interspersed along tamarisk (Tamarix cf. Africana) and Christ's thorn (Paliurus spinachristi) hedges.