Oleander (Nerium oleander) is a fragrant flowering evergreen shrub or small tree that is in bloom from spring through fall. The flowers form in large clusters and come in shades of white, yellow, pink, and red. Each flower has 5 petals that spread out like the blades of a fan. The slender, lance-shaped leaves have a smooth, leather-like feel.
Oleanders are fast-growing and can handle tough conditions, including drought, poor soil, salt spray, and the heat reflected off pavement and walls, such as found in hell strips and along highways. In the home landscape, they are great for providing a hedge or screening just about anywhere.
All parts of the oleander shrub are poisonous to humans and pets and ingesting them, even in small amounts, can be fatal. In addition, the smoke from burning oleander is toxic and contact with the flowers and leaves can cause severe allergic reactions. It is best to wear long sleeves and gloves when working near an oleander.
However, given a safe location, oleander shrubs are very ornamental and easy-care additions to the landscape.
You will get the most prolific flowering in full sun, but oleander shrubs will tolerate partial shade.
Oleanders are not frost-tolerant. They are only reliably perennial in USDA plant hardiness zones 8 - 10. In cooler areas, they can be grown in containers and brought indoors for the winter.
Mature Plant Size
Oleanders can reach a height of 20 ft. or more. They can be kept smaller by pruning, but you will have to keep at it.
Period of Bloom
Oleander plants will repeat bloom from spring through fall. Deadheading will help freshen the plant and encourage it to fill out but is not absolutely necessary.
Planting Oleander Shrubs
Oleander is not at all fussy about soil. They will do equally well in heavy clay and sand. Although they prefer a neutral soil pH between 6.5 to 7.5, they will adapt wherever they are planted.
Although oleander can adapt to poor soil, if your soil is less than ideal, you should add some organic matter, such as compost, at planting time, to improve water absorption and help the plant get established.
It also helps to keep the plant regularly watered, until you see new growth and know the roots have taken hold.
Caring for Your Oleander Plant
The major maintenance will be pruning after flowering to keep the plant full and bushy. Although you do not need to prune an oleander shrub, pinching the tips in early spring will encourage the plant to fill out, rather than become leggy. You can also prune to shape your plant or keep its size in check. This is best done in late fall.
Oleander shrubs can handle periods of drought, but they will be healthier and look fresher if they get regular water. However, do not let them sit in wet soil for prolonged periods during winter when they can be prone to root rots. The leaves will yellow if the roots are allowed to remain damp for too long.
Supplemental feeding should not be necessary, once your oleander is established. They will adapt wherever they are planted.
Pests and Problems of Oleander
Generally, oleander plants are problem free, but there are a few pests and diseases to be on the watch for.
- Mealybugs, scale, and aphids are the most common pests. They can usually be controlled with insecticidal soap or neem.
- The Oleander caterpillar can defoliate plants. Use Bt for control.
- There is also a leafhopper known as the glassy-winged sharpshooter that spreads a fatal oleander disease. It is most commonly found in California.
- Root rots can occur in cool damp soil.
- Oleander leaf scorch, mostly seen in California, is a bacteria, Xylella fastidiosa, spread by the glassy-winged sharpshooter, which causes yellowing and drying of the leaves. There is no cure of oleander leaf scorch and glassy-winged sharpshooters are hard to control.
Using Oleander in the Landscape
A single oleander in the garden will give you color throughout the season. Since the plants can get quite larger, you will need to keep a specimen plant pruned to fit the space it is given.
Oleander shrubs are commonly used as hedges and make a great screening, whether for privacy or to hide eye-sores like air conditioning units.
If you choose to grow oleander, be aware that the plants are very poisonous and should not be grown where young children and gnawing pets will be playing.
Some of the Best Oleander Varieties to Grow
With new introductions every year, it is hard to pick the best plant varieties for a garden, but these oleanders have stood the test of time.
- “Hardy Pink” lives up to its names. It will grow to about 15 ft. in height and 10 ft. wide, with pink flowers throughout summer.
- “Mathilde Ferrier” has double pale yellow flowers and show some resilience against frost damage. It reaches a height of about 8 ft. tall.
- “Mrs. Lucille Hutchings” is covered with double blossoms in a peachy hue. This is a large oleander, topping out at 20 ft. tall and 10 ft. wide.
- “White Sands” is a dwarf oleander variety that doesn’t get much larger than 4 - 6 ft. tall and wide. It has lovely pure white flowers.