Forests and smaller wooded areas within the park are comprised mainly by cork oaks (Quercus suber), Portuguese oaks (Quercus faginea), Pyrenean oaks (Quercus pyrenaica), olive trees (Olea europaea), alders (Alnus glutinosa and Alnus incana incana), holly trees (Ilex aquifolium), bay laurels (Laurus nobilis), rhododendrons (Rhododendron ponticum), ferns, mosses, and lichens.
The charity also organises working holidays called "Thistle Camps" on various properties, with activities undertaken including footpath maintenance and woodland work such as rhododendron control.
Rhododendron | rhododendron | Rhododendron ponticum | Rhododendron tomentosum | Rhododendron luteum | American Rhododendron Society | Rhododendron vaseyi | Rhododendron subg. Hymenanthes | Rhododendron selense | Rhododendron rex | Rhododendron neoglandulosum | Rhododendron ferrugineum | Rhododendron aberconwayi | MV ''Rhododendron'' | MV Rhododendron |
Much of the area is however becoming invaded by the alien plant, Rhododendron ponticum which provides a covering of pink blossom in May and June, but which is slowly blanketing out the native flora.