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Oleanders are great subjects for sunny areas. These
plants are also highly drought tolerant and are
excellent selections for seaside plantings where
they can be protected from salt spray. You can
choose from several forms including tree forms,
shrub, and groundcovers. As mentioned earlier,
oleanders are great as a "living fence" or screen
and even take well to container culture. While
oleanders require regular watering during
establishment, they are able to take droughty
conditions better than many plants. Hand-in-hand,
these landscape subjects have low fertilizer needs.
Established plants actually have little to no
supplemental fertilizer requirements.
Regular training and maintenance pruning will help
in optimal appearance and flowering. Wear gloves to
avoid contact with the toxic properties of the
plant. Young oleanders may develop excessive
"suckers" or water sprouts that can affect the
overall appearance of the plants. These excessive,
unproductive growths can inhibit flowering and
should be removed. Removing all old flower heads
will also increase flowering. Rejuvenation pruning
can bring older plants back into prime condition.
While many people conduct an annual severe pruning
campaign, this can induce excessive growth and, as a
result, fewer flowers. Rejuvenation pruning
involves removal of a portion of the older stems
over a three year period. Basic instructions
include removal of one third of the old stems to the
ground level the first year. The second year remove
one-half of the remaining old stems and head back
(shortening the stem a bit to just above a bud or
existing shoot) any long new shoots. The third year
prune out the remaining old stems and again head
back the new shoots. The resulting plant then
flowers anew on the fresh, productive wood.
Oleanders are generally pest-free. However, while
you would think that a toxic plant such as oleanders
would have few pests able to consume the poisons,
there are a few creatures able to cause some
problems. One such problem pest that I will mention
is the oleander caterpillar. This moth larva is
probably the most common pest of oleander brought
into our office for identification. These
caterpillars have an interesting behavior that
avoids most of the toxic plant. They bite the plant
veins which allow the toxic sap to drain before they
consume the leaf matter. Common in March, July and
December, the adult female moth lays up to 75 orange
eggs. The moth is beautiful and easy to identify -
purple-black wings covered with white dots. The
caterpillars can be controlled when small with the
biological control, Bacillus thuringensis or Bt
available at most garden centers. Used according to
label instructions, this least toxic material
affects only caterpillars.
As mentioned earlier, the oleander is considered a
toxic plant. They can poison or kill both humans
and livestock. Symptoms of poisoning from
consumption of leaves includes severe
gastroenteritis, diarrhea, abdominal pain, sweating
and weakness. Heart rate is also affected. If
ingestion is suspected, immediately contact a
physician, hospital or poison control center. To
prevent poisonings, plant oleander at sites in your
landscape where people will not come in direct
contact. Parents should avoid planting oleander in
their landscapes where small children could
accidentally consume the plant. Never burn this
plant when disposing of pruned branches! The
volatile oils will become airborne and may cause
respiratory problems from inhaling the smoke. Also,
keep pets and livestock away from this plant.
Oleanders do not have to be kept from all
landscapes. However, education of workers and
residents as to common sense precautions and plant
placements will limit the danger of poisoning.
For more information on flowering shrubs and
poisonous plants,
please contact our
Master Gardeners
on the Plant Lifeline at 764-4340 from 1 p.m. to
4 p.m. Mondays, Wednesdays and Fridays. Our office is located
at
25550 Harborview Road, Suite 3
in Port Charlotte. Our Plant Clinics are available
across the county:
Demonstration
Garden at 7000 Florida Street, Punta Gorda from
9 a.m. to
11 a.m every Thursday. Englewood/Charlotte Public Library 9 a.m. to
noon every Monday.
Ralph Mitchell is the county extension director/horticulture agent for the
Charlotte County Cooperative Extension Service. You
may contact him by e-mail
Ralph.Mitchell@charlottefl.com
You may also contact a volunteer
Master Gardener from
1 p.m. to
4 p.m. Monday, Wednesday and Friday at 764-4340 or by e-mail Master.Gardener@charlottefl.com
Resource:
Culbert, D. F. (1995) Oleanders for
Florida,
The University of Florida Extension Service, IFAS.
Ralph E. Mitchell is a Horticulturist
and Charlotte County Extension Agent
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