Commonly known as rowan trees, American mountain ash are popular ornamentals in gardens and are widely used as street trees given how easy they are to grow and how they can tolerate both climate and weather. Mountain Ashes are also beautiful year-round. In spring and summer months they produce showy white flowers while in autumn they produce vibrant orange berries. Mountain Ashes are often targeted by wood-burrowing pests, fungi that weakens the tree and diseases that can be transmitted to other trees in the area. Proper pruning and consistently spraying for pests and diseases will keep Mountain Ashes looking their best and thriving.