The sources do not give one universal schedule: UF/IFAS describes one yearly fertilization, while UCANR describes 10-10-10 once a month during a container plant’s growing season. Keep the choice tied to region, container conditions and label.
How to fertilize Nerium oleander
Feed oleander only during its active outdoor growing season. Container guidance includes a 10-10-10 monthly example, but no universal dose or schedule is established.
Check for active growth
When to fertilize
Feed only in the active outdoor growing season described by the sources. Reduce water in fall as oleander enters dormancy and do not carry a growing-season schedule into a cold, resting plant.
Follow the product label
Fertilizer type and dose
UCANR specifically names 10-10-10 for a container during the growing season. UF/IFAS does not specify a product in its yearly statement, so 10-10-10 is not a universal requirement.
No container concentration or application volume is provided. Follow the product label rather than converting an unspecified landscape dose.
Inspect a stressed plant before feeding
When not to fertilize
Yellowing or weak growth alone cannot tell you whether feeding, water, roots, light, or seasonal stress is responsible. Check those conditions before changing fertilizer.
Sources
- Royal Horticultural SocietyBotanical details; Cultivation and toxicity
- University of California Agriculture and Natural Resources, Tulare/Kings County Master GardenersFor the Love of Oleanders, Fertilization and seasonal water sections, PDF page 1
- University of Florida Institute of Food and Agricultural Sciences ExtensionUse and Management; Fertilization and Florida climate sections