The flora in the Glenarm area is diverse and many rare species are present.
In Straidkilly, between Glenarm and Carnlough, part of the nature reserve has alkaline soil from the underlying limestone. This gives rise to a mass of colour in springtime.
Unusual plants found include Wood Vetch, Toothwort, Twayblade, Stone Bramble, Lesser Winter Green , Bird’s-nest Orchid and Yellow Bird’s-nest.
Walking through Glenarm Forest in spring, the scent of wild garlic is all around. Throughout the Glen, the glades are beautiful with the sight of bluebells. Further up the Glen the rare Wood Cranesbill can be found in summer. Conservation work is being done to increase numbers of this plant.
Down by the seashore plants such as Sea Kale, Sea Thrift and Sea Campion can be found. On higher ground above Glenarm different species of heathers, thistles, buttercups, vetch and many more moorland plants flourish.