Chinese Pistache Sudden Decline: Weed Killer, Circling Root, Transplant Shock

Two Chinese Pistache; one leafed out then wilted/browned. Twig test: some green under bark, some dead. Weed killer sprayed around base; grass seed + Miracle-Gro applied. Sandy soil, fast drainage. 10 yrs old.

Assessment

• Twig test mixed—prognosis guarded.
• Homeowner weed killers usually safe if off foliage.
• Check bark for damage.
• Wait 2–3 weeks; if declining, replace.

Follow-Up: Circling Root Cut, Yellowing New Leaves

Found girdling root, cut partial section (sterilized tools). Cool, wet, cloudy weather followed. New leaves yellowing.

• Too soon to blame root cut.
• Likely transplant shock (root adjustment period).
• Some leaves may drop—energy conservation.
• Patience + adequate water.
• Deep, infrequent watering > frequent shallow.
• Mulch 3" max, away from trunk.
• Reference: Tree Owner's Guide (PDF).

Expert insight provided by Steve.