What is beautiful, but deceitful and poisonous? This blog usually focuses on things biological, so it must be an animal or a plant, and perhaps it could be either. In this case it is the oleander shrub that fits that description.
Oleander is such a popular addition to roadside plantings and gardens that it now occurs world-wide in warm, wet Mediterranean type climates where its long-lasting profusion of white, pink, or red flowers brighten up the landscape. It is remarkably drought-tolerant and protects itself from being munched by herbivores by sequestering toxic cardiac glycosides in its tissues, from its roots to the tips of its leaves. No wonder it’s the dominant plant along freeways in California.
Oleander is, in fact, one of the more poisonous plants, but mammals, especially humans seem to be more sensitive to its toxins than birds. However, folk tales about drifters during the Dust Bowl years dying from having stirred their stew with oleander twigs are probably false.
Clearly, oleander is beautiful and poisonous, but what about being deceitful? How can a plant be deceitful?
But oleander flowers produce no nectar, and thus there is no reward for pollinators to keep exploring the profusion of flowers on the plant. It’s false advertising and deceptive on the part of the plant. But does it work, that is, does enough pollination occur to allow seeds to be produced?
Apparently, insects that pollinated this oleander explored many of the flowers in a cluster, moving enough pollen to produce several seed pods. But the number of seed pods on the entire plant is scanty.
The only good news for bee pollinators is that the lack of nectar in the flowers means they would not contaminate their honey with cardiac glycoside poisons.