Oleander (Nerium oleander) grows as a rounded shrub, or it can be trained as a small, single-trunked tree with foliage at the top. This evergreen has many branches of foliage that is dense and dark green, offering a privacy screen if planted in groups or borders. Delicately shaped, showy, fragrant flowers tend to be pink, while varieties range from red, orange, yellow, and white. Blooming for an especially long period, flowers come spring to summer and sometimes early fall and year-round in warmer climates. Common nicknames for the plant include Jericho rose and rose laurel. Native to the Mediterranean and beloved since ancient Roman times (possibly earlier), oleander is hardy in USDA zones 8 through 11. The plant grows between 6 and 20 feet tall and 10 to 15 feet wide, each leaf measuring 8 to 10 inches long, each flower between 1 and 3 inches in diameter.
|Common Name||Oleander, Nerium, Jericho rose, rose laurel|
|Botanical Name||Nerium oleander|
|Plant Type||Evergreen shrub/tree|
|Mature Size||10 to 18 ft. tall, 10 to 15 ft. wide|
|Sun Exposure||Full sun to part shade|
|Soil Type||Fertile, adaptable|
|Bloom Time||Spring to summer, sometimes early fall and year-round in warmer climates|
|Flower Color||Orange, pink, red, white, or yellow|
|Hardiness Zones||8-11, USA|
When shopping for an oleander bush, find one that is one or two years old with a strong, straight, central stem. Cut off all the other stems completely and any side branches on the main stem to about half their length. Support the plant with a bamboo stake. Place the stake in the soil right by the stem and use plant ties to connect the stake with the stem.
Oleander prefers full sun, but it will also tolerate part shade. It is also tolerant of heat, drought, wind, and coastal conditions.
Plant in well-drained, fertilized soil for best results. Oleander shrubs will also adapt to poor soil, sandy soil, and a range of pH levels. Like many native Mediterranean plants, oleanders prefer alkaline soil, but they will grow in acidic or neutral soil, adapting to pH levels between 5.0 and 8.3. Before planting, test the pH level of the soil. If the soil is overly acidic, mix in ground limestone, oyster shells, or wood ash.
Water whenever the top inch of the soil becomes dry, then let the plant grow and the roots reach for moisture. If transplanting an oleander from one pot to another, choose a larger container that has drainage holes to prevent the plant from becoming root-bound.
Feed poor soil with a little bit of a balanced fertilizer during the plant's first spring. Moving forward, established oleander won't need regular fertilizing.
Temperature and Humidity
Oleander can tolerate light frost and temperatures as low as 20 degrees Fahrenheit. In climates where temperatures reach any lower than that, grow the plant in a container and bring it indoors for winter.
Types of Oleander
Among many cultivars, consider the following:
- 'Calypso', which is very hardy and has single, cherry red flowers
- 'Isle of Capri', which has single, light yellow flowers
- 'Sister Agnes', which has single white flowers
- 'Compte Barthelemy', which has double red flowers
- 'Mrs. Roedin', which has double pink flowers
- 'Hawaii', which has single salmon-pink flowers with yellow centers
- 'Petite Pink,' 'Petite Salmon', 'Variegata,' and 'Variegatum Plenum', which are all dwarf types.
Oleander can be propagated by stem cuttings.
Pinch tips of young stems to prevent legginess and welcome the shrub to branch out. Prune any damaged or diseased limbs and prune to shape it in late autumn. As side branches grow, prune them back to the trunk on the main stem. Let leaves remain. Fasten the central stem to the trunk as it grows bigger and taller using plant ties, and replace the original bamboo stake with a 5-foot wooden tree stake as needed. To train the plant, cut off the top when it reaches a desired height.
Bring oleander inside in colder zones. Before winter weather comes, cut the bush back generously by about two-thirds. If the plant is established in the ground, dig around the roots cautiously. Pot the plant in good soil. Place in an area that is sheltered but still has full sun such as a porch or a garage with a window.
Common Pests and Plant Diseases
Oleander leaves have latex inside and extracts from the plant make a strong insecticide. For this reason, plants are resistant to deer and rarely have severe issues with diseases or pests. They are especially resistant to Verticillium wilt. Even so, keep an eye out for Sphaeropsis gall, false oleander scale, and aphids. The most damaging pests are oleander caterpillars. Mature caterpillars can move up the walls of adjacent buildings and reproduce near the eaves. Remove cocoons to manage the next generation, which could eat all the plant's foliage in a week or two.
Is oleander easy to grow?
Yes, highway departments often choose oleander for roadside plantings. Shrubs need only minimal care in the garden.
How fast does oleander grow?
They grow at a medium to fast pace, growing 1 to 2 feet or more per year. Even established plants that have been damaged by cold temperatures can regrow rapidly from the base.
What is the difference between oleander and rhododendron?
Oleander is native to Asia while rhododendron has a hybrid origin. Oleander grows in riverbanks and dry rocky watercourses, but rhododendron grows most prolifically in moist forests. Oleander is hardy in USDA zones 8 through 11; rhododendron is hardy in zones 4 through 8.