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Fertilizing Mature Doug Firs, Blue Spruce & Arborvitae

Central NJ lot with mature Doug firs (40–50 ft), 3rd/4th year blue spruce and arborvitae. Asked for fertilization advice.

The expert said mature trees usually don't need fertilizer. If desired, use 13-13-13 at 1 lb per inch trunk diameter, scattered 6 in. from trunk, watered in.

Fertilizer Guidelines

Mature trees: rarely need it.
If fertilizing: 13-13-13 balanced.
Rate: 1 lb per inch trunk diameter.
Keep 6″ from trunk; water in.

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