In addition to the geological interest of the site, the range of plants growing on Brean Down has led to it being designated as a Site of Special Scientific Interest. The nationally rare white rock-rose (Helianthemum appenninum) is a common species at the site, occurring in abundance on the upper reaches of the grassy south-facing slopes. Some of the broomrapes growing here, which were originally thought to be oxtongue broomrape (Orobanche artemisiae-campestriae), are now no longer believed to be this species, but atypical specimens of ivy broomrape (Orobanche hederae). Other plants on the southern slopes include the Somerset hair grass, wild thyme, horseshoe vetch and birds-foot-trefoil. The northern side is dominated by bracken, bramble, privet, hawthorn, cowslips and bell heather.