Oleander (Nerium oleander) is a fast-growing evergreen shrub that's hardy and fairly low-maintenance. In fact, because of its hardiness, the plant is considered invasive in certain parts of the Southwest and around the Gulf Coast. It produces fragrant, showy clusters of flowers from around May to October, coming in several color varieties.
Oleander is typically grown as a perennial landscape ornamental in warm climates, but it also can work as a container plant for sunny patios and decks. It is fast-growing and reaches 4 to 8 feet tall on average, with some cultivars reaching 20 feet high. It is adaptable to many unfavorable conditions, including drought, urban heat, salty air, and poor soil.
While oleander is a beautiful shrub, all parts of it are toxic to people and animals. Ingesting any part can cause serious symptoms or even death. Skin contact also can result in irritation, such as rashes and sores, so it's important to wear gloves and protective clothing when working with oleander. Never burn any part of this plant, as the smoke from burning it is toxic.
Oleander has an upright, rounded growth habit with a slightly smaller spread than height. During the warmer months, the shrub is full of showy, five-petaled flowers that grow in clusters on each stem. It sports narrow, dark green, lance-shaped leaves that are roughly 4 to 7 inches long. On young plants, the leaves are more of a glossy, light green color.
|Botanical Name||Nerium oleander|
|Common Name||Oleander, East Indian oleander, Jamaica South Sea oleander, laurier rose|
|Plant Type||Broadleaf evergreen|
|Mature Size||4 to 8 feet tall and 4 to 5 feet wide|
|Sun Exposure||Full sun to part shade|
|Soil Type||Average fertility, medium moisture|
|Soil pH||6.5 to 7.5|
|Bloom Time||Spring through fall|
|Flower Color||Pink, purple, red, yellow, white|
|Hardiness Zones||8 to 10|
|Native Area||Asia, Europe|
|Toxicity||Toxic to humans and animals|
Oleander Plant Care
In the garden, some people use oleander shrubs as hedges, screens, and borders. While they provide excellent ornamental value, they also can crowd out less hardy garden plants. Considering the high toxicity of the oleander shrub, it's wise to restrict it to secure, private areas of your landscape, such as in an enclosed backyard.
Oleander is native to dry and rocky Mediterranean soil, so it's able to tolerate poor soil and some drought. Its roots are also known to readily spread and become invasive. So if you ever want to remove your shrub, it can be a difficult task to rid your soil of its extensive root system.
Oleander is native to the Mediterranean region, and it’s been naturalized in many parts of Europe and Asia. In the United States, it’s hardy in growing zones 8 to 10, though some gardeners in cooler climates are able to overwinter it as a container plant indoors.
The shrub is typically found growing around stream beds that occasionally experience drought. It can tolerate some frost but struggles once the temperature falls below 20 degrees Fahrenheit. Oleander prefers average soil with a neutral pH, medium moisture, and good drainage. Its growing site should get partial to full sunlight.
Oleander shrubs prefer full sun but tolerate some shade. More sun means more flowers.
The ideal soil pH is neutral, between 6.5 and 7.5, but oleander will grow outside of that range. It also tolerates a variety of soil types, including clay and sand. Poor soil should be amended with compost before planting. Plants grown in containers should have well-drained soil.
Water your oleander regularly, but let the soil dry out between waterings. Keeping the soil damp can cause the leaves to turn yellow. Be particularly careful not to overwater in the winter, which promotes root rot.
Temperature and Humidity
Oleander grows outdoors in zones 8 to 10. It is not frost-tolerant but can endure limited, light frost. If you live in a climate that freezes, you can grow the plant in a container and bring it indoors for the winter. However, it's best to minimize the amount of time it spends indoors, so try to leave it out in the cold until the temperature goes below 20 degrees Fahrenheit, and bring it back out as soon as it warms up in spring.
Oleander typically does not need to be fed, but some varieties may benefit from a small amount of nitrogen fertilizer; check the care instructions that come with your plant for recommendations.
Is Oleander Toxic?
There are multiple poisonous elements to oleander. All of its parts—the flowers, leaves, stems, sap, etc.—are toxic, even when they’re dried or burned. The plant is a potent source of cardiac glycosides, which can cause irregular heart activity. Even eating a single leaf or drinking water from a vase with an oleander flower can be lethal to a small child, though the mortality rate is generally low in humans.
Oleander can affect animals in the same way based on their size and how much they ingest. Poisonings typically occur in farm animals, such as cows and horses, when they are allowed to graze in areas where oleander is present. Plus, dogs and cats can be poisoned when they are allowed to investigate an oleander plant on someone’s property. Even wild birds succumb to the plant’s toxicity.
If you do choose to keep oleander on your property, make sure no children or pets can come in contact with it. Also, wear long sleeves, pants, and gloves when working with your shrub, and wash your hands afterward.
Symptoms of Poisoning
Symptoms generally show up within hours of contacting the plant. And in some cases, especially with small animals and young children ingesting the plant, the first sign that a poisoning took place is, unfortunately, death.
The following are some moderate to severe symptoms that a person or animal might experience from oleander:
- Irregular heartbeat
- Low blood pressure
- Vision disturbances
- Diarrhea, nausea, vomiting, or stomach pain
- Loss of appetite
- Difficulty breathing
- Rash or hives
Moderate cases last one to three days on average; severe cases might require hospitalization. If you suspect oleander poisoning has taken place, contact a health care provider or poison control center immediately.
Varieties of Oleander
- 'Hardy Pink': Pink flowers; relatively cold-hardy; 8 to 15 feet tall and 6 to 10 feet wide
- 'Mathilde Ferrier': Double pale yellow flowers; 8 to 15 feet tall and wide
- 'Mrs. Lucille Hutchings': Large cultivar; double peach-colored flowers; 20 feet tall and 10 feet wide
- 'White Sands': Dwarf variety; white flowers; 4 to 6 feet tall and wide
- 'Petite Salmon': Dwarf variety; salmon pink flowers; 4 to 6 feet tall and wide
- 'Hawaii': Large pink flowers with yellow throats; 10 to 18 feet tall and up to 12 feet wide
Pruning an oleander is optional, but it will help to keep the shrub more bushy and less leggy. Prune after the flowers are done blooming. You can also do some grooming in late fall to shape the shrub and/or limit its size. During the growing season, deadheading the spent flowers throughout the bloom period will encourage more flowers.
Common Pests and Diseases
A few pests can cause problems with oleander plants, including aphids, mealybugs, and scale; treat any of these with neem oil or insecticidal soap. If the foliage seems to be disappearing, it could be due to the oleander caterpillar, which can be fought with Bt. Oleanders in specific regions, particularly California, are susceptible to a bacterial disease spread by the glassy-winged sharpshooter, which is very difficult to control.
How to Remove Unwanted Oleander
Because of its fast growth habit and extensive root system, oleander isn’t easy to get rid of. Chemical herbicides are the fastest way to remove unwanted oleander. But they also can be highly toxic to the environment and dangerous for any people and animals who come in contact with them. Plus, herbicides can kill plants that you want to keep in your garden.
So if you wish to avoid chemicals, you should be prepared for a longer and more labor-intensive process to remove the oleander. The goal is to take out all of its roots. To do so, first cut the entire shrub to its base while wearing protective clothing. Be careful to gather and properly dispose of all parts of the plant. A helpful method is to put all of your cuttings on a tarp, so you don’t lose any.
Next, water the soil around the stump well to make it more workable. Dig around the perimeter, and pry up as much of the root system as possible. You might need to enlist help to lift the stump and roots out of the ground. Finally, continue to dig in the soil to remove any remaining roots. If any regrowth in the area occurs, get rid of the new shoots as soon as possible by digging them up from the roots.