Why Plants Die
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Oleander

Nerium oleander, Apocynaceae

Sources last read 14 September 2026.

Forgiving Among the more tolerant plants here.

Also called East Indian oleander, Jamaica South Sea rose, laurier rose, rose bay, Rose Laurel, Rosebay and sweet-scented oleander.

Oleander (Nerium oleander), the whole plant.
Ji-Elle, CC BY-SA 3.0 · Wikimedia Commons

Oleander is toxic

  • Toxic to cats. Toxic principle: Cardiac glycosides. Clinical signs: Drooling, abdominal pain, diarrhea, colic, depression, death. ASPCA
  • Toxic to dogs. Toxic principle: Cardiac glycosides. Clinical signs: Drooling, abdominal pain, diarrhea, colic, depression, death. ASPCA
  • Toxic to people. Toxic when eaten, and the smoke produced by burning it is harmful. Use gloves and protective gear when handling it. RHS

What the sources say about its care

Sources file this plant under other names: Nerium oleander L (RHS). Citations below point at the name its source uses.

Light
Full sun
RHS, filed as Nerium oleander L · read 13 September 2026
Water
Moist but well-drained
RHS, filed as Nerium oleander L · read 13 September 2026
Humidity

No source read publishes a humidity figure for any plant on this site. What follows is general guidance for foliage plants.

ASHRAE recommends indoor relative humidity between 30% and 60% 30–60%
Penn State Extension · read 13 September 2026
Temperature

How cold this tolerates, not what it prefers. No source read for this site publishes a preferred range for a plant indoors.

H3 — -5 to 1°C -5 to 1 °C
RHS · read 13 September 2026
Soil
Chalk, Clay, Loam, Sand; pH Acid or Alkaline or Neutral
RHS · read 13 September 2026
Toxic to cats
Toxic
ASPCA · read 13 September 2026
Toxic to dogs
Toxic
ASPCA · read 13 September 2026
Harmful to people
Toxic when eaten, and the smoke produced by burning it is harmful. Use gloves and protective gear when handling it.
RHS · read 13 September 2026

How it usually goes wrong

Brown brittle margins with a green centre

The oleander shows browning on many leaves at once, all at the margin, with no spots or soft patches anywhere.

Leaf margins are the end of the water supply, so they are the first tissue to run short when the air takes more than the roots can send. Penn State Extension cites 30% to 60% as the recommended indoor range, and a heated room in winter sits below it. That applies while it is grown indoors; its RHS rating of H3 describes a plant that also grows outside, where the air is seldom that dry.

Telling it apart: Where the plant stands. Browning concentrated on the side facing a heater points at the air.

Penn State ExtensionOleander brown leaf tips and edges: causes
Flowering stops while the foliage carries on

The oleander looks well in every other respect: green, firm and growing. What is missing is the flowering.

Buds are formed only when the plant has energy to spare. Its source places it in full sun, and in less light than that the surplus that pays for flowers is missing.

Telling it apart: The spacing of the newest leaves. Stretched growth means the light is short; normal spacing points at timing or feeding.

RHSDiagnose no flowers or dropped buds on this Oleander
Lower leaves collapse and yellow within days of a watering

Colour goes before shape on a oleander. The lowest leaves on each stem yellow evenly, stay soft to the touch, and the compost two inches down is still wet from the last watering.

The source for this plant describes moist but well-drained soil. Compost that stays saturated loses the air spaces fine roots grow into, and those roots die back first.

Telling it apart: Weigh the pot in your hand. A pot still heavy a week after watering is holding more water than the roots are using.

RHSDiagnose yellowing leaves on this Oleander
Split, browned leaves on the side of the plant facing the wind

After a windy spell the oleander shows dry brown edges and torn leaves on its exposed side. New growth that follows is undamaged if the weather settles.

A plant listed for a sheltered site by its source is not built for sustained wind, which both dries its leaves and damages them physically.

Telling it apart: Whether it followed stormy weather. Damage that appeared overnight after wind is weather; damage that develops over weeks is something else.

RHSOleander brown leaf tips and edges: causes
Washed-out patches that do not spread to the shaded side

The oleander shows pale, dry patches only where direct sun reaches, often with a sharp edge between damaged and healthy tissue.

Sun through a window on a still day heats a leaf far above the air around it. Its source describes full sun; the glass adds the heat that does the damage.

Telling it apart: Whether it appeared after a move. Scorch follows a change in position within days.

RHSOleander spots on leaves: causes

Not sure which it is? Ask the diagnosis questions for Oleander.

Routine care

Propagation
Oleander can be propagated by seed or stem cuttings.
NC State Extension · read 13 September 2026
Sow seed, take semi-hardwood cuttings, or air layer in spring.
RHS · read 13 September 2026
Pruning
When winter is over, cut back dead and frost-damaged branches. Light pruning after each flowering improves its shape.
NC State Extension · read 13 September 2026
Pruning group 9. Under glass, restrictive pruning may be needed in late winter. Tolerates hard pruning.
RHS · read 13 September 2026
Pests and diseases
Can be troubled by oleander aphid, milkweed bug and spinose scale, plus sooty molds.
NC State Extension · read 13 September 2026
Under glass, glasshouse red spider mite, mealybugs and scale insects can attack it. Disease risks: it is a high-risk host of Xylella fastidiosa, and honey fungus occurs rarely.
RHS · read 13 September 2026

Move something and watch

Loading the simulator. It needs JavaScript; the care table above does not.

About the plant

Nerium oleander, the oleander, is a shrub or small tree native to the Mediterranean region east to southern Asia, from Morocco and Portugal east to India and Myanmar; the Flora of China also cites it as native in Yunnan in China. It is the only species currently classified in the genus Nerium, belonging to subfamily Apocynoideae of the dogbane family Apocynaceae. It is also cultivated widely in temperate and subtropical areas as an introduced ornamental and landscaping plant.

From Wikipedia, CC BY-SA 4.0 · read 13 September 2026

Native range
Medit. to Myanmar
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Europe, Asia
NC State Extension · read 13 September 2026
Mediterranian to W China
RHS · read 13 September 2026
Climate
subtropical
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Growth form
shrub or tree
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Perennial, Shrub; habit clumping, erect, rounded
NC State Extension · read 13 September 2026
Bushy (evergreen)
RHS · read 13 September 2026
Size
Height 60–234 in; width 72–120 in
NC State Extension · read 13 September 2026
Height 1.5-2.5 metres; spread 1-1.5 metres after 10–20 years
RHS · read 13 September 2026
Flowering
Flowers cream/tan, gold/yellow, orange, pink, white; blooms in spring, summer
NC State Extension · read 13 September 2026
Flowers pink in summer; red in summer; white in summer
RHS · read 13 September 2026

Common problems with Oleander

More of the Apocynaceae family

Plants with similar care

Sources

What this does not cover

The figures above are what published sources say, not measurements of the plant in your room. They say nothing about your pot size, your water, the season, or how far from the glass the plant stands, and those decide more than any figure here does.

Humidity has no species figure because no source read for this site publishes one, and the only temperature published for this plant is a cold floor. The simulator fills those gaps with general figures for its kind of plant, marked as general and listed on how we read sources. Where a toxicity row says the plant was not assessed, that is the absence of a finding and not a finding of safety.

If something is already wrong, the diagnosis tool asks about the soil, the window and the watering, which is where the answer usually is.