Shrub · Apocynaceae
Oleander
Nerium oleander
A tough, drought-proof shrub that blooms all summer and asks only that you respect one thing: every part is dangerously poisonous.
Full sun
Every 7–14 days
USDA 8–10
5–20 ft · 1.5–5.9 m
Overview
Oleander is a forgiving, fast-growing evergreen that thrives right where fussier plants give up, taking drought, salt spray, and poor soil in stride. It rewards a warm-climate garden with months of pink, white, or salmon flowers from late spring deep into summer, so you get a lot of bloom for very little worry. Given room, it can reach 20 feet (6 m) tall, yet it takes hard pruning just as happily, which is why so many gardeners keep it as a relaxed hedge or screen.
The same toughness that makes it so easy comes with one thing you truly need to know. All of it, from root to flower, holds cardiac glycosides that affect the heart, and it counts among the most poisonous shrubs people plant near a home. That danger does not soften in dried leaves, in the smoke of burning clippings, or in the water a cut stem has stood in, so it pays to keep this front of mind.
None of that should scare you off, because the answer is simply thoughtful placement. Keep it clear of pastures, play areas, and vegetable beds, handle it with gloves, and never burn the trimmings, and you and everyone around you stay safe. Treated with that little bit of care, it gives back one of the longest, most reliable bloom seasons you will find on any shrub.
Care
The short version: give it full sun and well-drained soil, water deeply but let it dry between drinks, and prune to shape after it flowers. It asks for very little once it settles in, and mistakes are easy to recover from, but every part of it is poisonous, so keep your gloves handy.
Light
Oleander loves full sun and blooms its heart out in it, though it will still get by in partial shade with fewer flowers to show for it. The more direct sun it soaks up, the fuller the plant grows and the heavier its flush of bloom, so a bright spot pays you back.
Water
Water regularly while a new plant is finding its feet, then simply let the top half of the soil dry out before you water again. Mature oleander is genuinely drought-tough and copes fine with poor, salty ground, so it needs watering only every 7 to 14 days at most. Ease right off through winter for anything you keep in a container.
Soil
You do not need to fuss over soil here, because it grows in clay, loam, sand, or shallow rocky ground and even puts up with poor or salty conditions. Good drainage matters far more than rich soil, and it stays happy across a wide pH band of 6.0 to 7.8.
Temperature
Oleander shrugs off real heat, up to about 100°F (38°C), without a fuss. It handles a light freeze down to roughly 19°F (-7°C), but a harder cold snap can damage or kill it, which is why gardeners bring container plants in or overwinter them cool.
Humidity
Average outdoor humidity suits it just fine, with no target you need to chase. It tolerates dry air and coastal salt spray with ease, so this is one thing you can happily leave alone.
Feeding
Feed seasonally from spring through summer with a balanced general-purpose fertilizer, and it responds well. Plants settled into the ground want very little once established, while those in pots appreciate a regular light feed through the growing season.
Pruning
Prune lightly to shape after flowering, from late summer into early fall. Flower buds form on new growth, so cutting back later than early fall costs you next year's bloom, which is easy to avoid once you know. Deadhead the spent flowers, wear gloves for the whole job, and never burn the clippings.
Repotting
Container oleander likes moving up every 2 to 3 years, or sooner if roots circle the pot, water runs straight through, or growth stalls. Step it gently into a slightly larger pot with fresh, well-drained mix, gloves on, and it carries on happily.
Size & spacing
Plants range from about 5 to 19.5 feet (1.5 to 6 m) tall and spread 6 to 10 feet (1.8 to 3 m) wide, so a full-size hedge really does want some room. Dwarf cultivars stay far smaller and settle nicely into a large container, so there is a fit for most gardens.
When to plant
Oleander is happiest in the mild end of the temperate range, roughly zones 8 to 10, so most warm gardens suit it well. Start cuttings or seed in late winter to early spring, move young plants outside once the last frost has passed, and the flowers keep coming from late spring through late summer.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: late winter to early spring
- Plant: spring after last frost
- Harvest: late spring through late summer
Hardiness
USDA hardiness zones: 8–10
Temperature: down to -12°C
Troubleshooting
Oleander is an easygoing plant that rarely causes headaches, and when something does turn up it almost always shows on the leaves rather than the whole shrub. Find what you are seeing below and act on it early, and it sorts out quickly. Just keep your gloves on for any job that means touching the plant.
Leaves nibbled down until only the veins are left
When a branch turns to lace almost overnight, the oleander caterpillar is usually the culprit, since it feeds in busy groups and works through foliage fast. Take heart, because this is easy to get on top of. Put your gloves on and pick the orange, black-tufted caterpillars off by hand, then trim away any branch that is truly overrun. If an outbreak gets ahead of you, a treatment of Bacillus thuringiensis will settle it.
Fix:
- Hand-pick and destroy caterpillars (wear gloves)
- Remove and dispose of heavily infested branches
- Apply Bacillus thuringiensis (Bt) for severe infestations
Sticky leaves and a dark film with little bugs tucked beneath
If the leaves feel tacky and a black film is creeping over them, look for oleander aphids in bright yellow, or now and then some scale or mealybugs, gathered on the fresh growth. The sticky honeydew they leave is what the sooty mold feeds on, and none of it will hurt the plant for good. Start by knocking the lighter groups off with a firm spray of water, then follow up with insecticidal soap or horticultural oil. A second treatment breaks the cycle, and the mold rinses away once the bugs are gone.
Fix:
- Spray off light infestations with a strong jet of water
- Apply insecticidal soap or horticultural oil to affected growth
- Repeat treatment to break the pest cycle and wash off sooty mold
Spotted leaves that begin to fall
Brown or yellow spots with neat, tidy edges usually mean a fungal leaf spot has settled in, though the sooty mold from insect honeydew can leave lookalike marks, so give the plant a gentle once-over. Nothing here is cause for worry. Pick off the marked leaves, tidy any that have dropped around the base, and thin the plant a little so air moves through it. Keeping water off the foliage gives the spores far less to work with, and the plant recovers on its own.
Fix:
- Remove and destroy affected leaves
- Improve air circulation and avoid overhead watering
- Clean up fallen debris around the plant
Toxicity
This is one of the more dangerous plants you can grow near a home, and it helps to know that clearly. Every part holds cardiac glycosides that can stop a heart, and the poison lingers in dried leaves, in burning smoke, and in vase water. A single leaf has killed children, and it is rapidly and often fatally toxic to cats, dogs, horses, livestock, and birds. Keep it well away from anyone who might taste it and never burn the clippings, and you can grow it with real peace of mind.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Severe
A cat that tastes any piece of this plant is in genuine trouble, so please treat it as urgent. You may see drooling, vomiting, diarrhea, and belly pain first, then an uneven or racing heartbeat, weakness, and collapse. Even a tiny mouthful can be deadly, so get help right away rather than waiting.
Dogs Severe
Dogs are in the same real danger from just one chewed leaf or stem, and quick action makes all the difference. Drooling, vomiting, and diarrhea can turn into worrying heart rhythm changes, tremors, and a sudden collapse. Head straight to a vet instead of hoping it passes on its own.
Horses Severe
Horses are remarkably sensitive here, and only a few leaves can be fatal, so caution truly matters. Colic, drooling, and diarrhea come on together with a badly irregular heartbeat, muscle tremors, and collapse. Even dried clippings that drift into a paddock are every bit as dangerous as the living plant.
Rabbits Severe
The heart toxins are very hard on rabbits, and even a small amount can stop the heart, so keep them well clear. Watch for gut pain, a refusal to eat, weakness, and a faltering pulse. There is simply no safe nibble here, so place oleander somewhere they can never reach.
Livestock Severe
Cattle, goats, and sheep are poisoned by fresh green leaves and by dried clippings raked into hay just the same, so store trimmings carefully. Vomiting, colic, diarrhea, and a staggering heartbeat give way to collapse and sudden death. Many losses happen when trimmings get tossed over a fence, which is easy to prevent once you know.
Birds Severe
Birds are affected too, and the same heart toxin can take them quickly, so keep them at a safe distance. You might notice weakness, a ruffled stillness, an erratic heartbeat, and a sudden death. Keep poultry and pet birds away from every part of the plant, and you take the risk off the table.
People Caution
No part of oleander is safe to eat, and a single leaf has been enough to kill a child, so treat it with real respect. Swallowing any of it can bring on vomiting, a dangerously uneven heartbeat, and death, and the sap can irritate skin. Wear gloves, never burn the clippings, and keep children well back, and it stays a safe plant to enjoy.
Wear gloves when handling or pruning; never burn clippings; wash hands after contact; keep all plant parts, prunings, and vase water away from pets, children, and livestock.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Oleander comes in a lovely range of flower colors and a few sizes, from compact dwarf forms to tall hedging types, so there is likely one to suit your spot. These are among the cultivars you are most likely to come across.
Hardy Pink
This pink-flowered pick is loved for shrugging off more cold than most, which makes it a reassuring choice if your zone sits right on the edge.
Petite Salmon
A tidy little dwarf with soft salmon blooms, it stays well under the size of the wild species and settles happily into a snug corner or a big pot.
Sister Agnes
If you want height in a hurry, this vigorous white-flowered one grows tall and fast and has long been a favorite for screens and hedges.
How to propagate
Oleander is genuinely easy to multiply, and cuttings are far and away the surest way to copy a plant you already love. Whichever route you take, keep your gloves on, because every part you handle is poisonous.
Stem cuttingsEasy
Late spring through summer · 2-4 weeks to root
Cuttings are the friendly, dependable way to make more oleander, and the new plants come out just like the parent you took them from. Snip softwood or semi-hardwood stems from late spring through summer, and they settle in within 2 to 4 weeks, even in a plain glass of water on a sunny windowsill. Keep your gloves on the whole time, since the cut stems and their sap are poisonous.
SeedModerate
Late winter to spring · Several weeks to germinate; seedlings vary
Seed is the slower, less predictable path, and that is perfectly fine to try if you are curious. Sow from late winter into spring and the seeds need several weeks to sprout, with seedlings that often turn out looking nothing like the parent. Handle them gently and keep your gloves on, because the seeds carry the same toxin as the rest of the plant.
Myths
Only the leaves are dangerous, so the flowers, smoke, and vase water are harmless.
It is kinder to know the truth up front: every part of oleander is poisonous, from the bark, flowers, and fruit to the leaves, roots, sap, seeds, and stems. Drying does not take the danger away, the smoke from burning clippings is toxic to breathe in, and even the water a cut stem has stood in can poison someone. A single leaf can be enough to kill a child or a pet.