Magnolia 'Yellow Bird' Decline: Alkaline Compost pH Shift

14-year-old Magnolia 'Yellow Bird' suddenly brown leaves, dieback. Only change: light topdressing of local compost/sand/mushroom manure mix. Vancouver spring (rainy).

Cause

Magnolias need acid soil (pH ~5.0). Compost/manure often alkaline → raises pH → nutrient lockout → yellow/dark green leaves, decline.

Fix

• Test soil pH (garden center kits).
• Remove topdressing if possible.
• Lower pH: ISU Guide to Lowering Soil pH