Saguaro Oozing Sap: Bacterial Necrosis and Arm Salvage

A 15-ft saguaro (Carnegiea gigantea) with old car damage now oozing dark sap, gray mushy base, and irrigated landscape indicates fatal bacterial necrosis (Erwinia cacticida). Arm removal for propagation is the only preservation option.

Diagnosis: Bacterial Necrosis

• Entry: Old wound (car impact) never fully sealed
• Trigger: Irrigation = excess moisture + soil pathogens
• Progression: Rot spreads upward; ooze = bacterial exudate
• Outcome: Always fatal; structural failure imminent

Immediate Actions

1. Stop irrigation in root zone immediately
2. Hire professional for arm removal (crane required)
3. Select arms: Undamaged, straight, 3-4 ft sections
4. Cut: Clean cuts; mark north orientation

Arm Propagation Protocol

1. Callus 3-4 weeks (shade, horizontal)
2. Plant 6-8" deep in 50% sand / 50% native soil
3. Orient north-south as marked
4. Zero water 4-6 weeks; then only rainfall
5. Shade south side 6 months if orientation uncertain

Success Reality

• Rooting rate: 30-50% for large arms
• Time to roots: 12-24 months
• Time to growth: 18-36 months
• Professional salvage increases odds

Main Trunk Removal

Schedule crane removal before monsoon. Dead saguaros fall unpredictably. Stump grinding prevents trip hazards.

The irrigation that "didn't seem like much" was the death sentence. Saguaros evolve on 3-5" annual rain—any supplemental water in desert soils risks rot.