Ash, Oak Leaf Mountain Overview Category: Ornamental trees Common Name: Ash, Oak Leaf Mountain Botanical Name: Sorbus hybrida 'Oak Leaf' Sun Exposure: Full sun Height: 25-30 ft. Spread: 18-20 ft. See notes | Back to ornamental trees Notes A hybrid derived from European Mountain Ash and Swedish Mountain Ash. Leaves are lobed like English Oak. It has orange-red berries. This tree is also fireblight resistant.