Brown tips can follow drought or heat stress, salt or boron injury, excessive wetness or root trouble, cold damage, caterpillar feeding, and oleander leaf scorch from the oleander strain of Xylella fastidiosa.
Why Nerium oleander leaves get brown tips
For outdoor Nerium oleander, brown tips or margins call for a moisture, salt, cold and pest check. Do not treat the color as one cause.
Check the leaves, stems and pot
What kind of brown mark is it?
Record browning or dead tissue at leaf tips or margins, whether yellowing came first, and whether the pattern affects one branch or much of the canopy.
Compare uniform yellowing or drooping across branches with browning that moves inward from tips and margins. Check whether decline stays on one branch, whether watering restores turgor, and whether caterpillars or other pests are present.
Use the visible signs to choose the next check
Possible causes and next checks
Check root-zone moisture and drainage before changing irrigation, review salt or fertilizer exposure, inspect new shoots and leaf undersides for caterpillars or sucking pests, and seek local plant-health support when one-branch marginal scorch continues to spread.
Watch for new damage or recovery
What to watch on new leaves
Recheck new leaves, the direction of marginal browning, branch-by-branch progression, soil moisture and pest activity after conditions are stable. Continuing dieback should be referred to a local extension or plant-health service.
Do not diagnose from one sign alone
What brown tips cannot tell you
Sources
- Royal Botanic Gardens, Kew: Plants of the World OnlineAccepted name; cultivation; hazards
- North Carolina State University Extension Gardener Plant ToolboxDescription; container and houseplant locations; insects and diseases
- University of Florida IFAS ExtensionOleander leaf scorch; oleander caterpillar; recognition and contributing factors
- University of California Agriculture and Natural Resources Statewide IPM ProgramSymptoms; drought-stress comparison; Xylella fastidiosa context