Evergreen Shrubs Turning Rust Color: Mite Damage vs. Salt Injury

Evergreens developing rust-colored foliage with well water high in sodium suggest two distinct problems. Salt injury typically causes uniform browning from tips inward, often on the side facing the irrigation spray. But rust color with a stippled appearance points to spider mites.

Test for mites: shake a branch over white paper. Tiny moving specks (red, brown, or black) confirm mites. They thrive on drought-stressed plants—salty water exacerbates stress. Treat with horticultural oil or a specific miticide (not general insecticide), covering leaf undersides thoroughly. Repeat in 7-10 days.

If no mites, consider Phytophthora root rot (causes rusty needles, poor drainage) or rust fungi (orange pustules on leaf undersides). Both need lab diagnosis and specific fungicides.

Long-term: install a rainwater catchment or filtration system for irrigation. Salty well water accumulates in soil, eventually killing most landscape plants.