Sweet briar is an erect perennial shrub, commonly growing 1.5 to 2 m high but can be up to 3 m.
Many stems arise from a shallow, perennial rootstock. They are smooth when young and become rough and woody as the plant ages. They arch towards the top and have numerous backward curving flat thorns up to 1.5 cm long.
The leaves are pinnate and have an apple-like fragrance. They consist of 2 to 4 pairs of oval leaflets plus one terminal leaflet. The leaflets have serrated margins and short prickles on the leaf stems.
Flowers usually appear in late spring and are pink or white with 5 petals and long green sepals or leaflike structures at the flower base. They form in loose clusters at the ends of the branches and are also fragrant.
The fruits are orange-red in colour, oval shaped with short spines and contain numerous, yellow, irregularly shaped seeds. The sepals remain attached to the fruit.
The extensive roots are at least 1 m long and are usually confined to the top 30 cm of soil.