Oleander

Oleandar
Oleandar

If you are looking for a screening shrub that grows really fast you want an oleander. Flower come in pink or white varieties. There are small versions of oleanders as well that will not take over the place.

Oleander grows well along the coast, the edges of forests and in home gardens. It grows from between 3′ and 30′ tall. Flowering occurs through out the warm season. Plant in full sun for best flowering.

While it can withstand cool temperatures, ice is a threat, as are several extended freezes. Only the older established Oleanders survived last winter’s cold. Oleanders bend easily under the weight of water and ice and must be protected from breaking. The oleander grows so quickly though you could also just trim back broken branches once the weather breaks.

Once established they are drought tolerant but need regular watering the first year while they settle in.

Pruning is not necessary, but oleander will flower better if pruned. Remove suckers and prune after flowering is done for the year. Severe pruning will hurt flowering. Remove suckers, dead branches, branches that have over grown other branches and just lightly to keep the shape of the plant nice. The end of Feb is the best time to trim it in the Houston area. Since the milky white sap is poison, be sure to wear gloves and keep your fingers away from your face while pruning. The sap also irritates some people’s skin. Dispose of cuttings where children and pets will not get into them.

Oleanders have Cardenolide Glycosides in the sap. It can cause death in sufficient quantities. It is very bitter tasting and nauseating so it is unlikely you’ll be eating much of it. Fumes from burning oleanders are also toxic. Because it is so common it is a favorite plant of poisoners and suicides. So toxic is it, that like rhododendron, honey made from the flowers may be toxic as well. Do not toss oleander cuttings in the compost pile, it can remain toxic even in the compost for almost a year.

Oleanders are believed to be native to the Mediterranean and were transported to warm regions around the world from there by early traders in the early 1800s.

Watch for leaf scorch both bacterial ( see comments below ) and from dry windy conditions. The leaf scorch from windy, dry weather can be treated by watering more frequently and deeply.

Aphids can be a problem, treat with soapy water or orange oil. They may cause black sooty mold to grow on your plant. The black soot can be washed off with soapy water.

Scale and caterpillars will also attack oleander. Treat scale with orange oil. Caterpillars I’m not sure of a good treatment.

That  said I’ve had not a single problem with any of my oleanders until the cold winter of 2009-2010. All of my miniature oleanders died. Many of my neighbors large oleanders are heavily damaged but look like they will come back once the weather warms. Just remove frost damaged branches and they should be fine.

Stay away from the dwarf oleanders they are not drought or cold tolerant and prone to scale.

More information:
International Oleander Society

10 thoughts on “Oleander

  1. From Atlanta, I am inquiring about the presence of Oleander Leaf Scorch (OLS) bacterial disease in Houston (for my son who soon will move his family back from Hong Kong and buy his 3rd Katy house). I always help him with landscaping and include oleander, which we love. By chance, I found web links to Southern CA, AZ, and Central Texas about OLS problems in those areas. The vector is a glassy-winged sharp-shooter (GWSS) that is spreading a new strain of bacterium Xylella fastidiosa to oldeanders. Are gardeners in Houston having any problems with oleander leaf scorch disease? The articles stated that OLS is in the Southeast, too, but I can’t grow oleanders here and have no first-hand information. Thank you.
    Marci

  2. So far I have not seen it here on the north west side of the city.

    However, it has been reported at Moody Gardens on Galveston Island which is within the Houston area. So I suspect it will be here soon.

  3. More information:
    Oleander Leaf Scorch causing major damage in Central Texas

    Leaf Scorching ( pdf )

    Oleander leaf scorch ( has some photos )

    The leaves begin to yellow, then brown edges first, hence the name. Symptoms usually show in July and Aug.

    There is no control. Once a plant has leaf scorch it must be removed. Leaf scorch is spread by insects, especially the sharpshooter insect. Any leaf sucking insect can spread bacterial disease among plants.

    Leaf scorch does not only affect oleanders. There is a similar bacterium that causes Pierce’s disease in grapes in Texas. Oaks, elms and sycamores are also susceptible to leaf scorches. The browning is caused by bacteria clogging the veins of the leaves which cuts off nutrients and water to the leaf.

    There are reports that infected oleanders that were cut to the ground regrew healthy in Arizona. So try that first if it strikes your plants. I also have a note here that tetracycline injected 2xs yearly into a plant may control the bacteria. This is an expensive undertaking though.

    If in doubt TAMU has a plant diagnostics lab which at this time is charging $30 to diagnose plant problems.

  4. I am new to the Houston area and had landscaping installed at my house. I have 3 oleander patio trees, 15 gal size. About 75% of the leaves on 2 of the trees have turned bright yellow and are dropping. The tops continue to be green and are blooming. I am wondering if I have over watered and if the roots are dying. Can trees recover if this is the case?

    Thanks,
    Ellen

  5. I think they will be just fine.

    Many plants drop leaves after being moved.

    Oleanders are pretty tough. They manage to survive our monsoons and droughts quite well. Just give them a bit less water and I’m sure they’ll be fine.

  6. I live in NW Harris County (NW Houston suburb) and I think we have the oleander scorch here. I had a row of 5 oleanders and I lost 2. I dug them up and replaced them. Now 2 more are showing signs. I plan to remove all 5 this summer. I’ve also noticed many plants around the area showing the symptoms. So sad these plants were wonderful.

  7. There isn’t a great deal you can do. You can spread the oleanders out, clumps will attract more leaf hoppers than stray bushes. And you can keep an eye out for leaf hoppers and hose down the plant frequently to push them off the plant.

  8. I live in Central Florida, near the Gulf Coast. I just want to pass along my experiences with caterpillars.

    Here’s my moth/caterpillar control plan:
    I can see my 1-year old oleanders fron the house and, periodically, I have seen Polka-dotted Wasp Moths near the oleanders.
    I go out and eliminate them, right in mid-air.
    I also have found the eggs on the leaves, sometimes arranged in a perfect rectangluar or matrix-like pattern. They are sometimes laid in the crotch of the stems. They are grayish-white and about the size of a pin head. I just crush them.
    I also go on patrols for caterpillars, and when I find them or the webbing I eliminate them. The cycle is short so you have to go out about once a week to be really on top of the situation.

    So far my efforts have been sufficient and my leaf damage minimal.

    Bruce Slater

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