Oleanders (Nerium oleander) are evergreen shrubs or small trees in the dogbane family Apocynaceae. It is the only species currently classified in the genus Nerium. It is native to a broad area from Morocco and Portugal eastward through the Mediterranean region and southern Asia to Yunnan in southern China.
This tree has been cultivated in the Caribbean for centuries and its popularity continues today because it produces abundant flowers. A wide variety of soil tides and moisture regimes are tolerated by the oleander, from dry sandy soils, to moist clay soils. Also, they are tolerant of soils with high levels of salt content. Oleanders make excellent wind breaks, but damage sustained by flowers during high winds can destroy both open blossoms and flower buds.
This ornamental shrub or small, densely branched tree grows three to 30 feet tall. The many branches form a vertically upright shrub with smooth bark varying in color from pale green to light gray. The leaves are dark green above and lighter in color below and will turn yellow before dropping. Although flowering occurs year round, the most plentiful flowering occurs during the warmer months.
Each cluster of flowers develops on the tips of branches and is composed of several 3- to 4-inch red, pink, yellow or white flowers.
Oleander is one of the most adaptable landscape plants for tropical locations, as they offer fast growth, showy ever blooming habit, and adaptation to full sun and poor soil conditions.
All parts of the oleander are poisonous; because of this the plant should be restricted to locations where direct contact with people will be limited. It is not recommended that oleanders be eliminated from landscapes, but a better approach is to educate people to treat them with respect and to place them where the danger of poisoning will be limited.
Parents should avoid planting oleander in their home landscape where there is a potential for small children to consume parts of this plant. When disposing of branches pruned from oleanders, do not burn the branches: the volatile oils that make the plant poisonous will become airborne and may cause respiratory difficulties if the smoke is inhaled.
Pet owners and livestock producers also are cautioned to place this plant out of the reach of animals that may graze on it.
According to the American Medical Association Handbook on Poisonous and Injurious Plants, all parts of the oleander plant contain toxic principles. The most significant of these toxins are oleandrin and neriine, which are cardiac glycosides. Many people in the landscape industry have spent years working with oleander without experiencing oleander poisoning from landscape workers or from plants in the landscape.
Oleander can be a serious threat to small children who like to put things in their mouths and they may be attracted to oleander because of its bright flowers. All parts of the plant though contain poisons, and if any oleander is swallowed it can lead to problems like nausea, vomiting, extremely low blood pressure, heart problems, and in rare cases even death. For this reason, it’s not a good idea to have oleander in gardens where small children play. Contact a physician, hospital, or poison control center if you suspect you have ingested part of this plant.
Protect Cayman’s Wildlife! For more information, to share your knowledge or if you would like to get involved with the many activities in the National Trust’s Know Your Islands Program, please visit www.nationaltrust.org.ky or call 949-0121.The weekly column from the National Trust is submitted by Marnie Laing, Education Programs Manager at the Trust.
Last week’s answer: Avoid standing under Manchineel when it rains; the milky sap which springs from any broken part of this tree is highly irritant!
Trivia question: What endemic bird has become extinct?
Look for the answer in next week’s feature!