Ehretia rigida can grow up to 9 m in height. The bark is very smooth and grey on new branches and rough on older branches and stems. The plant has an alternate leaf arrangement but the leaves seem to grow together in clusters at the tips of its short branches. The leaves can be smooth or covered with stiff hairs that are rough to the touch. It has small leaf stalks of about 2 mm long. The flowers grow in dense clusters on the branches. These pale mauve, blue or white flowers can only be seen in spring with male and female flowers on different plants. They have a diameter of 7 mm and are sweetly scented. The fruits are round, orange to red, turning black when ripe and are eaten by wild animals. Parasitic plants, such as the mistletoe, Viscum rotundifolium, are often found on the puzzle bush.