The height of P. dulce is commonly 10-15 meters, but ranges from 5 to 18 m. They are broad-spreading with irregular branches. The bark is grey, becoming rough, furrowed, and then peeling. Leaves are bipinnate, and leaflets oblong to 4 cm in length. Thin spines are in pairs at the base of leaves, and range from 2 to 15 mm in length.
Leaves are deciduous.
However, new leaf growth coincides with the loss of old leaves, giving the tree an evergreen appearance. The flowers are in small white heads 1 cm in diameter. Each flower has a hairy corolla and calyx surrounding about 50 thin stamens united in a tube at the base. The pods are pinkish, 1-1.5 cm wide, about 12 cm long, and become spiral as they mature. The pod splits along both margins.