Saving a Magnolia After Root Cutting for Walkway and Wall Installation

Situation

40-ft magnolia had roots cut on two sides for walkway (19″ from trunk) and wall (25″). Trunk 70″ circumference at base.

Impact

• Support not an issue. Water/nutrient uptake reduced → foliage dieback likely on affected sides.
• Dead foliage won't return. New growth may sprout from trunk, not old branches.

Remediation

• Water 1″/week (pan method). Deep watering preferred.
• Fertilize root zone: 1 lb (2 cups) 8-8-8 or 10-10-10 per 100 sq ft over area 3× canopy spread. Apply March, May, July, Sept.
• Bay Area (no rain until Oct): Irrigate all exposed soil areas.

Key Takeaway

Root loss causes permanent canopy reduction on that side. Intensive watering and fertilization support remaining roots and encourage new trunk sprouts.