The Common laburnum is a small deciduous tree 5 to 7 meters tall, with a smooth bark, dark green spreading branches and pendulous pubescent twigs (hair is longer and patent in Laburnum alpinum and appressed in Laburnum anagyroides). Leaves (composed of three leaflets) have a long petiole. Flowers are golden yellow, very fragrant, densely packed in long pendulous racemes (up to 25 cm long) and bloom typically in May (racemes have less flowers in Laburnum alpinum plants). Fruits are legumes with numerous black seeds that contain cytisine (an alkaloide) which make them extremely poisonous (mature legumes of Laburnum alpinum are winged, unlike the ones of Laburnum anagyroides).
Common laburnum is a light-loving plant (it dislikes the shade of thick woods) and forms small stands on the edge of copses. It grows and flowers in temperate and moderately damp habitats, especially in calcareous soils and is often associated with forests of hop hornbeam and beech. Farmers fight it because it is highly toxic, also for animals.
Its yellow-brown wood is hard and heavy, great for making posts, for woodturning and to use as fuel. In the past it was considered excellent for the construction of arches. Common laburnum is cultivated for ornamental purposes. It is used advantageously to reinforce unstable slopes along mountain roads and for environmental restoration.