Common nicknames for the plant include Jericho rose and rose laurel. Native to southern Asia and the Mediterranean and beloved since ancient Roman times (possibly earlier), oleander is hardy in USDA hardiness zones 8 through 10. Oleanders can be allowed to grow in their natural mound form, or they can be trained into a multi-stemmed or single-stemmed tree form. To create a single-stemmed tree, cut off all other stems and any side branches on the main stem to about half their length. Support the plant with a bamboo stake. Push the stake into the ground next to the stem and use plant ties to secure the stem to the stake. Deadhead spent blooms to prevent seed pods from forming.
Light
Oleander prefers full sun. It will also tolerate partial shade, but its foliage won’t be as dense. It is also tolerant of heat, drought, wind, and coastal conditions.
Soil
Plant in well-drained soil for best results. Oleander shrubs can adapt to many kinds of soil conditions: poor soil, sandy soil, and a range of soil 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
Water whenever the top inch of the soil becomes dry. If transplanting a container-grown oleander from one pot to another, choose a larger container with drainage holes to prevent the plant from becoming root-bound.
Fertilizer
Feed poor soil with light dose of a balanced fertilizer during the plant’s first spring and a light fertilization yearly thereafter. Moving forward, established oleander is not a heavy feeder.
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.
Oleander Cultivars
Among many cultivars, consider the following:
‘Calypso’ is very hardy and has single, cherry red flowers’Isle of Capri’ has single, light yellow flowers’Sister Agnes’ has large single white flowers and is often sold as ‘White Oleander’‘Compte Barthelemy’ has double deep raspberry flowers’Mrs. Roeding’, which has double pink flowers’Hawaii’ has single salmon-pink flowers with yellow throats’Petite Pink,’ ‘Petite Salmon’ are dwarf varieties three to four feet tallVariegata,’ and ‘Variegatum Plenum’ have variegated foliage.
Propagating
Oleander can be propagated by stem cuttings.
Pruning
The best time to prune oleanders is during late winter just before new growth occurs (February through March). Oleanders bloom in summer on new growth. Pinch tips of young stems to prevent legginess and encourage branching. Prune out any damaged or diseased limbs.
Overwintering
Bring container-grown oleander inside in colder zones. Before winter weather arrives, cut the bush back generously by about two-thirds. If the plant is established in the ground, gingerly dig around the roots to lift the plant out of the ground. Pot the plant in good potting soil. Place it in an area that is sheltered but still receives full sun such as a porch or a garage with a window.
Common Pests and Plant Diseases
Oleander leaves contain latex 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 aphids, mealybugs, and scale. 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.
