Oleanders for Florida - Okeechobee County Extension Service ...

Oleanders for Florida 1 

Daniel F. Culbert 2 

Oleanders are evergreen shrubs or small trees 

native to the Mediterranean regions of southern 

Europe and southwest Asia. Nerium oleander L. has 

been cultivated in Florida since 1565 and its 

popularity in the southern tier of the United States 

continues today because of its bountiful flowering 

habit. It grows well on sandy soils near the coast and 

is widely cultivated near roadsides, edges of woods, 

lawns and gardens. 

Sometimes called the "Rose Bay," oleander has 

become associated in this country with tropical 

gardens. This plant derives its common name from 

oleandra which means olive-like in Greek. Oleanders 

belong to the Apocynaceae or "Dogbane" family 

which includes Allamanda, Mandevilla, Carissa or 

Natal Plum, Frangipani, Confederate Jasmine, and 

Madagascar Periwinkle (Catharanthus roseus). 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. 

DESCRIPTION 

This familiar Florida exotic is an ornamental 

shrub or small, densely branched tree, 3 to 30 feet 

tall. The many branches form a vertically upright 

shrub with smooth bark varying in color from pale 

green to light gray. Two or three leaves with short 

petioles grow from each node. The foliage is 

evergreen, leathery, narrowly elliptic to linear elliptic, 

Fact Sheet ENH-116 

4 to 12 inches long, and a½to1inch wide, with 

entire margins. Foliage is dark green above and 

lighter in color below and will turn yellow before 

dropping. Some cultivars have variegated foliage. 

Flowering occurs on oleander the year round, 

with the most profuse flowering occurring during the 

warmer months. Each cluster of flowers (botanically 

called a cyme) develops on the tips of branches and 

is composed of several 3- to 4-inch red, pink, salmon, 

yellow or white flowers. The petals on each flower 

are about 1 inch long and have a fringed appendage 

at the base. Flower type may be single, with five 

petals; intermediate, with 2 superposed sets of petals 

(corollas); or double, with 2 or more whorls of petals. 

Fruits on oleander are uncommon, but when 

present the long narrow pods usually occur in pairs. 

Many tufted seeds are contained in the green to 

yellow fruits, which will be released when the brown 

pod splits open lengthwise. The foliage, flowers and 

fruit are shown in Figure 1. 

LANDSCAPE USE 

Oleander is one of our most versatile landscape 

plants for sunny seaside locations. Few evergreen 

shrubs are available for use in Florida that offer the 

fast growth, showy everblooming habit, and 

adaptation to full sun and poor soil conditions that 

oleander provides. Even fewer choices exist if high 

1. This document is Fact Sheet ENH-116, a series of the Environmental Horticulture Department, Florida Cooperative Extension Service, Institute 

of Food and Agricultural Sciences, University of Florida. Publication date: October 1995. 

2. Daniel F. Culbert, county extension director and environmental extension agent, Indian River County, Vero Beach, FL 32960-2558; Cooperative 

Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611. 

The term "plates," where used in this document, refers to color photographs that can be displayed on screen from CD-ROM. These photographs 

are not included in the printed document. 

The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational 

information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national 

origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office. 

Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / Christine Taylor Stephens, Dean

Oleanders for Florida Page 2 

tolerance to drought and salt are important. 

Figure 1. Foliage, Flower and Fruit of Oleander. 

Selection and hybridization have resulted in cultivars 

of various plant size, different flower colors and 

shapes, and longer bloom persistence. 

Oleanders are available for use as small 

"standard" trees, shrubs, ground covers, large fencing 

or screening shrubs, and as potted patio plants. 

Dwarf forms are available as large ground covers or 

container plants providing vivid, summer-flowering 

interest. For best results and minimum maintenance, 

be sure to choose a cultivar whose growth 

characteristics and ultimate size fit your intended 

landscape use. Table 1 lists common cultivars used in 

Florida. 

GENERAL CULTURE 

Oleander is adapted to climatic conditions 

throughout Florida. However, this plant may 

experience injury in cold weather. In northern and 

western Florida, it should be used where it can be 

protected from freezing conditions. While it is highly 

salt tolerant, it does not do well when directly 

exposed to salt spray. Plant it behind the dune lines 

for best results. 

Full sun is necessary for best flowering and for 

development of a full, fountain-shaped crown. In 

shade, it will grow lanky and produce few flowers. 

Oleander is tolerant of a wide range of soil types and 

grows well in sandy dry areas. It is adaptable to a pH 

range of 5.0 to more than 8.3. 

Oleander transplants easily. For best results, 

plant container-grown oleanders during early 

summer when in active growth. Plants should be 

mulched to a depth of 3 inches. 

Newly planted oleanders should be irrigated 

regularly for the first few months to aid in 

establishment. Standards or larger specimens with 

stem diameters greater than 1-inch benefit from 

regular irrigation for one year. Oleander is very 

drought tolerant once established, but moist soils or 

irrigation stimulate growth. 

Oleander has low fertility requirements. 

Established plants usually do not need fertilizer 

because root systems extend into lawns where they 

can absorb nutrients from turf fertilizers. Growth of 

small plants may be stimulated with up to 3 

applications per year of a complete fertilizer. Use a 

rate of 1 pound nitrogen per 1000 square feet applied 

to the area within 1½ to 2 times the canopy diameter. 

Organic sources of nutrients and slow-release 

inorganic fertilizers will provide for longer periods of 

fertilizer availability. 

Pruning 

Young oleanders characteristically develop 

multiple stems. If a plant is to be grown as a 

"standard," the smallest stems should be removed 

leaving one main stem for a single-trunk specimen. 

Oleanders generally require some pruning for best 

flowering. "Suckers" or water sprouts may develop 

along the lower portions of main stems or from roots. 

Excessive suckering, especially with young plants, will 

inhibit flowering. Tip pruning to remove old flower 

clusters will increase the number of blooming tips. 

Dwarf cultivars occasionally grow tall shoots that 

must be removed to maintain the planting as a 

ground cover. Shoots of some dwarf and miniature 

cultivars occasionally die to the ground, and this dead 

wood should be removed when noticed.


Figure 2. Rejuvenation pruning for oleanders: A) First year, B) Second year, C) Third year, D) Result 

If severe pruning is necessary to improve plant 

shape or form, prune oleanders anytime after the rate 

of flowering has fallen. Oleanders are often pruned 

hard on an annual or regular basis. Such severe 

pruning can induce excess vegetative growth, basal 

sprouting, and fewer, but larger, flower clusters. 

Generally, the natural clumping type shape is 

preferred in hedges and screen plantings. Removal of 

one-third of the older stems or canes in successive 

pruning over three years is preferred to a complete 

cutting back of the plant to ground level. This is 

called rejuvenation pruning, as illustrated in Figure 2. 

Here are the steps: 

A) First year: Remove one-third of old mature 

stems near ground level. 

B) Second year: Remove one-half of the 

remaining old stems and head back long new 

shoots from last year’s growth. 

C) Third year: Remove the remaining old stems 

and head back the long new shoots. 

D) The desired Result will be apparent at the end 

of the third year of growth. 

The time to prune may be dictated by personal 

preference, but avoid late fall or winter pruning which 

encourages frost sensitive new growth. 

Pests 

Oleanders can be one of the most pest-free 

landscape plants with proper placement and pest 

monitoring. Primary pests are the oleander 

caterpillar, oleander scale, and occasionally aphids. 

Witches’ broom is a serious plant disease of oleander. 

Bacterial gall and mushroom root rot are other plant 

diseases that may be encountered. For current 

pesticide recommendations, please contact your 

county’s Cooperative Extension Service. 

The Oleander caterpillar (Plate 1) is the most 

significant insect pest of oleanders. The caterpillar is 

an immature (larval) phase of the Oleander Moth, 

Syntomeida epilais jucundissima. The adult female 

moth lays clusters of 25 to 75 orange eggs under 

leaves. Young larva will skeletonize the leaves, while 

the more mature, orange-colored caterpillar with 

black spots and hairs will eat the entire blade. By 

biting the veins, the caterpillar drains the toxic sap 

before consuming the leaf. 

When it reaches a mature size of about 2 inches 

long, the insect pupates. The silk-covered cocoon 

yields a purple-black winged moth that has several 

white dots on the wings. With a sixty-day life cycle, 

this pest can have three generations in a year. 

Scouting for the eggs and young caterpillars in March, 

July and December will enable control measures to 

reduce feeding damage. Bacillus thuringensis 

insecticides can provide environmentally safe yet 

effective control. Chemical insecticides also can be 

used. 

Oleander scale, Aspidiotus nerii, are common on 

many plants in our subtropical area. These small (1-2 

mm) whitish insects are found on either the top or 

bottom surface of the leaf, and are round in shape. 

Their hard, armored shell makes them difficult to 

control. Other scales that may be found on 

oleander include the black, dictyospermun, false 

oleander (Plate 2), Florida wax (Plate 3), 

hemispherical (Plate 4), nigra, and plumose scales. 

Other sucking insects affecting oleander may 

include the Oleander aphid, Aphis nerii, and the 

Longtailed Mealybug, Pseudococcus longispinus (Plate 

5). Aphids are yellow, soft-bodied insects which 

damage oleanders by inserting mouthparts into soft 

tissue and extracting plant sap. Aphids can reproduce 

rapidly. Heavy infestations distort leaves and stunt 

new growth.


One or more insect population peaks may occur 

at any time between May and September. Although 

many predatory insects feed on aphids, they usually 

cannot control the aphids. Regular scouting, removal 

of branches with high levels of infestation, and sprays 

of insecticidal soaps or horticultural oils are the most 

environmentally safe pesticides. Persistent problems 

may indicate a need for chemical insecticides. 

During feeding, aphids secrete droplets of a 

sugary solution called "honeydew." Drops of 

honeydew fall from the aphids onto leaves and stems 

below. This sugary solution promotes the growth of 

sooty mold fungi (Plate 6), Capnodium species. Sooty 

mold appears as a black staining or powdery coating 

on leaves and stems. The blackened leaves and stems 

are often the most obvious sign of aphid infestation. 

Although unsightly, sooty mold itself does not 

directly harm oleanders. However, the black fungus 

shades the leaves and reduces photosynthesis, 

potentially effecting the long-term vigor of the plant. 

Control of sucking insects will halt further 

development of sooty mold. Existing sooty mold on 

leaves will wear off through the actions of sun, rain 

and wind. Sprays of insecticidal soaps and 

horticultural oils for control of aphids and scales also 

help to loosen and remove sooty mold. 

Witches’ Broom is the most serious plant disease 

of oleanders. It is caused by a fungus, Sphaeropsis 

tumefaciens, which causes tip die back and the 

formation of a tight cluster of shoots from below the 

affected area. These shoots will grow only a few 

inches, turn brown and die. Infectious symptoms can 

appear in two to fifteen weeks after the infection 

occurs, and seem to be more common during cooler 

months. The fungus can be spread by wind, insects, 

or by infected pruning tools. 

No chemical fungicides are available to control 

witches’ broom, and no oleander cultivars are known 

to be resistant to this affliction. Affected stems 

should be pruned back at least 6 inches into 

unaffected wood. Look at the cut end of the stem to 

see if any discoloration from the systemic fungal 

growth is present, and prune back further if this is 

noticed. To prevent infection of unaffected plant 

parts, dip pruning tools in rubbing alcohol before 

using them on another branch or plant. 

Bacterial Gall is a plant disease occasionally seen 

as wart-like growths on oleanders. Spongy growths on 

leaves and longitudinal swellings on the stems result 

from the bacteria Pseudomonas syringae tonelliana 

entering wounds caused by insects or other agents. 

As with witches’ broom, prune out affected parts and 

sterilize pruning tools. 

Another plant disease of oleanders that is 

sometimes encountered is Mushroom Root Rot, which 

may be caused by the fungus Armillaria mellea or 

other fungal organisms. The plant appears to wilt 

because the crown areas have been damaged by the 

fungus, preventing the movement of moisture into the 

tops of the plant. Wet soil conditions encourage the 

fungus. Avoid over-watering and limit the use of 

heavy clay or muck soils; excessive mulching which 

covers up the crown also should be avoided. 

Propagation 

Oleander can be propagated vegetatively by 

softwood, semi-hardwood, or tip cuttings. Cuttings 

root easily when taken in early summer. Use of 

rooting hormone improves rooting percentages. Tip 

or air layers also may be taken to propagate 

oleanders. Because of the ease of vegetative 

propagation, use of seed to grow new oleanders can 

not be recommended except for plant breeders. 

Cultivars 

Many cultivars of oleanders have been selected 

and developed by private individuals, nurseries and 

public institutions. A tentative checklist of oleander 

cultivars lists 401 entries; of these about 175 are said 

to be currently available for horticultural use. 

Selected oleander cultivars are listed and described in 

Table 1. 

TOXICITY 

According to the American Medical Association 

Handbook on Poisonous and Injurious Plants, all parts 

of the oleander plant contain two toxic principles. 

These toxic principles, oleandroside and nerioside, 

both have been identified as glycosides. This 

extremely toxic plant can poison livestock and humans 

at any time of the year. Lethal doses of leaves for 

livestock have been established for horses (15-30 

grams), cows (10-25 grams), and sheep (1-5 grams). 

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. A 1961 report exists of 

flamingos being killed by oleander poisoning. There


are also reports that children in India died from 

eating the flowers and a report from Florida that 

persons using oleander sticks to cook hot dogs were 

poisoned. 

Symptoms 

Action of the poisons in oleander is similar to the 

action of the heart drug known as digitalis. The usual 

symptoms are severe gastroenteritis, diarrhea, 

abdominal pain, sweating and weakness. These signs 

appear within a few hours after eating the leaves. 

Cardiac irregularities are common, often 

characterized by increased heart rate. However, a 

slower heart rate is often detected in the later stages. 

Symptomatic treatment is suggested but is usually 

unsuccessful. Contact a physician, hospital, or poison 

control center if ingestion is suspected. 

Precautions with Oleander 

Because of its poisonous nature, the placement of 

this plant in a landscape should be carefully 

considered. The best use of this plant may be in 

areas where people will not come in direct contact 

with it. 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 who may 

graze on it. 

It is not recommended that oleanders be 

eliminated from all Florida landscapes. To do so 

would limit our choices of colorful flowering shrubs 

that thrive in adverse environmental conditions with 

minimal care. A better approach is to educate 

persons, workers and residents to treat them with 

respect and to place them where the danger of 

poisoning will be limited. 

REFERENCES 

Atilano, R.A. "Screening Oleander Cultivars for 

Resistance to Witches’ Broom." Proceedings of 

the Florida State Horticultural Society 94 

(1981):218-219. 

Broschat, Timothy K. & Meerow, Alan W. Betrock’s 

Reference Guide to Florida Landscape Plants. 

Cooper City, FL: Betrock Publishing Co., 1991. 

Gilman, Edward F. & Watson, Dennis G. "Nerium 

Oleander - Oleander" (Fact Sheet ST-412). 

Gainesville: Florida Cooperative Extension 

Service, March 1994. 

Graf, Alfred B. Exotica 4. East Rutherford: Roehrs 

Company, 1985. 

Johnson, Warren T. & Lyon, Howard H. Insects that 

Feed on Trees and Shrubs. 2nd ed. Ithaca: 

Cornell University Press, 1991. 

Lampe, K.F. & McCann, M. 1985. AMA Handbook 

of Poisonous and Injurious Plants. Chicago: 

American Medical Association. Distributed by 

Chicago Review Press. 

Pagen, F.J.J. Oleanders - Nerium L. and the Oleander 

Cultivars. Netherlands: Agricultural University 

Wageningen, 1988. 

Rose, Sylvester. "Nerium oleander." Gainesville: 

Florida Cooperative Extension Service, undated. 

Sanderford, Mark V. Acoustic Courtship 

Communication of the Polka Dot Wasp Moth, 

Syntomeida epilas Walker. Winston-Salem, NC: 

Wake Forest University, PhD Dissertation, May 

1992. 

Smith, Michael D., ed. The Ortho Problem Solver. 

2nd ed., 521-523. San Francisco: Ortho 

Information Services, 1984. 

Watkins, John V. & Sheehan, Thomas J. Florida 

Landscape Plants. Gainesville: University Presses 

of Florida, 1975. 

West, Erdman. "Poisonous Plants Around the Home" 

(Bulletin 175D). Gainesville: Florida Cooperative 

Extension Service, November 1993.


Table 1. Characteristics of Selected Nerium oleander Cultivars. 

Size Group and Cultivar Flower Color Flower Type Origin Comments 

DWARF (mature height 3-5 feet) 

Petite Salmon orangish-pink single 1973 Los 

Angeles 

Arboretum 

Petite Pink pink --- 1973 Los 

Angeles 

Arboretum 

Sister Agnes or Soeur Agnés white, cream 

throat 

TALL (mature height 10-25 feet or more) 

may be hedged to 3 feet; 

will grow to 6 feet, tightly 

branched. 

well suited for residential 

landscapes 

single 1868 France hardy, fragrant, large 

flowers, favored in 

California because spent 

blooms readily drop 

Atropurpureum dark purple-red single 1835 Belgium hardy, large blooms 

Calypso deep pink single 1975 Florida very hardy and vigorous, 

good blooming 

Carneum Plenum or Mrs. 

Roeding 

Comfe Berthelemy or 

Commandant Berthelemy 

salmon-pink double 1854 Germany somewhat weaker growth, 

persistent blooms slightly 

weeping growth habit 

red and pink 

with yellow 

margins 

superposed corollas 1898 France large flower 

Common dark pink to red single 79 A.D. 

Mediterranean 

an unimproved natural 

variety, unscented 

Hardy Red bright red single 1965 large flowers and 

inflorescences 

Isle of Capri light yellow single 1963 tender 

Pink Hawaii salmon pink, 

yellow throat 

single 1965 vigorous growth; an 

introduction used at Disney 

World 

Roseum rose pink single 1872 Italy profuse flowering, vigorous 

Variegatum pink single 1822 France vigorous; narrow gray green 

foliage with marginal 

variegation. 

Variegatum plenum pink with rose 

throat 

double 1978 Dark green foliage with 

marginal variegation 

White white single 1874 ---

Oleanders for Florida - Okeechobee County Extension Service ...

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