Weeping willows are fast-growing trees, adding up to 10 feet per year when young, but their average lifespan is a relatively short 30 years. ... Click Play to Learn How to Grow a Weeping Willow Tree. Common NameWeeping willow FamilySalicaceae Plant TypeTree Mature Size35–50 ft. tall, 5–50 ft. wide Sun ExposureFull 7 more rows Jun 22, 2022