By Angela O’Callaghan
Those lovely shrubs all over the valley, oleander, whose flowers range from pure white, through pink and red, to deepest magenta, amaze me. In full bloom along the roads they are gorgeous. Even the foliage is lovely, deep green leather straps.
Few plants are as well adapted as oleander to Southern Nevada conditions. They grow in almost any soil type, even our nutrient-poor soils. They tolerate drought, and survive a wide temperature range. Our summer highs temperatures do not kill them and they even endure lows of 5 degrees. When it gets that cold, the plant dies back, and returns in spring.
In other parts of the country, oleanders have some insect and disease problems, but not here. It is generally pest-free here. Some varieties grow up to 25 feet high, but most reach 8 to 15 feet, and spread about the same amount.
Being so plentiful in our landscapes, we must look at them more critically. We imported this plant from the Mediterranean, and you want to think when using such a robust, non-native plant.
They reseed themselves and produce new shrubs very easily. Unless you want an oleander forest, pick up the five-inch long seedpods.
A common question is: what to do with oleander prunings.
The absolute down side to oleander is that the entire plant is poisonous: fresh or dried leaves, twigs, roots, seeds and flowers. Even the sap, when it’s being pruned. Fortunately, the fresh leaves are said to be extremely bitter. The California Department of Food and Agriculture tracked dangerous plants and chemicals for 20 years, and found only one case of oleander poisoning in a human. That was, apparently, a deliberate act. Hungry animals, on the other hand, might be tempted to ignore the bad taste.
When leaves get dry or wilted, they may become more palatable, which is when pets are more likely to take an investigatory nibble. This is another good reason to clean up plant waste under or around oleander shrubs.
If you have oleander, enjoy them. When pruning them be vigilant to avoid accidents. Wear long pants and a long sleeved shirt and protective eyewear. Wash your hands after handling the shrub, or the handling sap, which can cause a skin rash.
Don’t burn oleander debris, since the smoke causes respiratory problems when inhaled.
People often ask staff of Cooperative Extension if oleander prunings should be put into compost, but there is no definitive answer.
Research on one of the toxins in oleander found that it became degraded in the composting process. But the other compounds may still be present in toxic amounts.
And can these be taken up by plants? Some evidence that indicates they can. I feel dubious about composting oleander debris. This is one of the very few things I regretfully suggest sending to the landfill.
Dr. Angela O’Callaghan is the Social Horticulture Specialist for Clark County Cooperative Extension. Contact firstname.lastname@example.org or 702-257-5581.