Oleander

Family:  Apocynaceae

Origin: Southern Asia and the Mediterranean

The Size: Height: up to 19 ft; width: up to 10 ft

Temperature & 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.

Lightning: 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.

The 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.

Watering: 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.

Reproduction: Oleander can be propagated by stem cuttings

Features of Care: 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.

Difficulties: 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.2 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.3 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.