Lavatera trimestris, common names annual mallow, rose mallow, royal mallow, regal mallow, common annual tree mallow syn. Althaea trimestris is a species of flowering plant native to the Mediterranean region.
This genus Lavatera is named after the Lavater brothers, 17th century Swiss physicians and naturalists. All species previously placed in Lavatera have now been transferred to the related genus Malva. Lavatera species are known as tree mallows, or rather ambiguously as rose mallows, royal mallows or annual mallows. The genus includes annual, biennial and perennial herbaceous plants and soft-wooded shrubs, growing from 1–3 m tall. The leaves are spirally arranged, and palmately lobed. The flowers are conspicuous, 4–12 cm diameter, with five white, pink or red petals; they are produced in terminal clusters. It can be invasive in the islands of Scotland.