Plant Care Guide

Oleander

Nerium oleander

Oleander is a heat-loving, drought-tolerant shrub famous for its clusters of colorful blooms and incredible toughness. Loved in coastal areas, highways, and landscapes across warm climates, oleander is one of the lowest-maintenance flowering shrubs available. It naturally grows into a dense mound but can also be trained as a single- or multi-trunked tree for a more sculptural form. 

Important: Oleander is highly toxic to humans and pets. Even the smoke from burning debris is dangerous. Always wear gloves and sleeves when handling the plant. 

Watering Requirements

While oleander is extremely drought tolerant once established, consistent moisture, without overwatering, produces the best growth and bloom set. 

Watering Guidelines 

  • Water when the top 1 inch of soil is dry 
  • Newly planted shrubs: water 1–2× weekly for the first month 
  • Established shrubs: water every 7–14 days during dry periods 
  • Container-grown oleander dries out faster → monitor more frequently 
  • Avoid soggy soil, this plant hates sitting in water 

Signs of Underwatering 

  • Drooping leaves 
  • Stunted growth 
  • Reduced flowering 

Signs of Overwatering 

  • Yellowing leaves 
  • Mushy stems 
  • Soil that stays wet for days 

Pro Tips

If your oleander’s leaves turn uniformly yellow, it is almost always overwatering. Reduce irrigation first before assuming nutrient issues.

Light Requirements

Oleander is a sun-lover and performs best when given abundant light. 

Best Exposure 

  • Full sun (6–8 hours) for maximum blooms 
  • Tolerates light shade, but foliage becomes less dense and flowering decreases 
  • Heat, wind, and reflected light (like from driveways) are not a problem 

Pro Tips

If your oleander is leafy but not flowering, it almost always needs more sun. Move or prune surrounding plants to increase direct light exposure.

Soil & Potting

Oleander isn’t picky about soil, which is part of its appeal. 

Soil Requirements 

  • Adaptable to poor, sandy, clay, rocky, or alkaline soil 
  • Prefers good drainage 
  • pH range: 5.0–8.3 (tolerant of high pH) 
  • If soil is extremely acidic, amend with lime or crushed oyster shell 

Potting 

  • Use containers 14–24" with drainage holes 
  • Select a well-draining potting mix 
  • Container-grown plants may require more frequent watering 

Pro Tips

If your oleander shows nutrient deficiency (pale leaves), always check pH first. Extremely acidic soil interferes with nutrient uptake. Correcting pH often fixes the issue without fertilizer.

Fertilizing

Oleander is not a heavy feeder and often needs no fertilizer at all. 

When to Feed 

  • Fertilize only if soil is poor or plant appears nutrient-deficient 
  • Apply a light, balanced slow-release fertilizer in early spring 
  • Avoid fertilizing late fall or winter 

Pro Tips

Over-fertilizing oleander causes long, weak, leggy growth with fewer flowers. Always start with the lowest possible dose and increase only if needed.

Pruning & Maintenance

Oleander can be shaped as a shrub or trained into a small ornamental tree. 

How to Prune 

  • Wear gloves & sleeves, the sap is toxic 
  • Best time: late winter to early spring 
  • Remove damaged, diseased, or crossing stems 
  • Pinch young tips to encourage branching 
  • Deadhead spent blooms to prolong flowering 

Tree Training

  • Choose one strong central stem 
  • Remove all side shoots up the trunk 
  • Stake for support until structure strengthens 

Pro Tips

Oleander blooms on new growth, so avoiding heavy pruning during active growth (spring–summer) ensures better flowering.

Common Problems & Solutions

Yellow Leaves 

Cause: Overwatering 

Fix: Reduce watering; improve drainage 

Sparse Foliage / Weak Blooming 

Cause: Too little sun 

Fix: Move to a sunnier location or prune shade-producing trees  

Dieback in Winter 

Cause: Frost damage 

Fix: Prune in spring; plant typically regrows rapidly  

Aphids, Scale, Mealybugs 

Cause: Typical ornamental pests 

Fix: Use insecticidal soap or neem oil; oleander is generally resistant  

Oleander Caterpillar 

Cause: Caterpillars eating foliage quickly 

Fix: Remove by hand or prune affected foliage; check for cocoons on nearby structures 

Pro Tips

If your oleander suddenly declines, check three things first: 

  1. Overwatering 
  2. Not enough sunlight 
  3. Frost exposure 

These account for nearly all oleander performance issues. 

Safety Notes 

Oleander is extremely toxic, even the smoke from burning pruned branches can be harmful. 

  • Do not plant where children or pets roam 
  • Always dispose of debris in the trash, never burn 
  • Wash tools and hands after handling