Saguaro Arm Drop & Trunk Cracks: Causes and Care

A homeowner reported that their 20-foot saguaro had one arm swing down 10 years ago, and recently two more arms dropped—one tearing off completely. A vertical crack also appeared from the base to mid-trunk. They wondered if the tree was dying.

Greg attributed the arm drop to cold damage weakening the attachment points. The crack, he explained, typically results from the cactus absorbing too much water too quickly, often after heavy rains. This can be exacerbated by old plastic landscape barriers that trap moisture.

Unless black ooze appears or the whole plant yellows and shrivels, the saguaro should survive. Greg advised monitoring for signs of rot but otherwise leaving the crack alone.

When to Worry

• Black, foul-smelling ooze from cracks indicates bacterial rot.
• Whole-plant yellowing and shriveling suggest systemic failure.
• Otherwise, cracks and dropped arms are often cosmetic.