Arnold Sentinel Austrian Pine Tree

Arnold Sentinel is a narrow, columnar selection of Austrian pine with dense dark-green needles. The Utah Water Conservancy District profile lists a mature size of about 25 feet tall by 7 feet wide and notes its value as a screen or specimen. Treat garden-size estimates as approximate, since growing conditions affect the dimensions reached. ## Appearance The upright form provides evergreen structure where a broad crown would take too much room. The long, dark needles remain on the tree through winter, making the narrow silhouette useful as a vertical accent or in a row. ## Growing Conditions Plant in full sun. The source lists a low irrigation requirement and USDA Zones 4–8; provide supplemental water during establishment and through the first few winters, especially in dry weather. Once established, the profile reports drought tolerance. ## Maintenance Use light, selective pruning to maintain the desired shape and prevent competing leaders. Monitor the tree for pests or disease, and check root-ball moisture during dry winters while it establishes.