Lemon Tree Stops Fruiting: Frost Damage, Rootstock Suckers, or Gummosis?

Why Did My Mature Lemon Bush Stop Producing Fruit?

A 10-year-old lemon in Southern California that suddenly fails to hold fruit may be suffering from frost damage, rootstock takeover, or gummosis (a fungal canker). Healthy leaves but aborted fruit point to vascular or hormonal disruption.

Diagnostic Steps

1. Check for frost damage: Did a hard freeze occur last winter? Bark splitting or dieback on upper branches suggests cold injury.
2. Inspect graft union: Growth below the graft is rootstock (often thorny, different leaves). Remove it completely.
3. Look for gummosis: Oozing amber sap, cracked bark, sunken cankers near soil line. Caused by Phytophthora.

Management

• Prune: Remove dead wood, low branches touching ground, and rootstock suckers.
• Spray copper fungicide on trunk and scaffold branches for gummosis.
• Fertilize appropriately: Citrus fertilizer in Feb, May, Aug. Avoid excess nitrogen.
• Water deeply every 7–10 days; adjust for rain.

When to Replace

If the tree is mostly rootstock, has extensive gummosis, or shows no improvement after a full season of care, replacement with a disease-resistant variety on a compatible rootstock is wise.

Consult a local citrus specialist for region-specific advice.