Bismarck Palms Failing in Southwest Florida

Abstract

Growing up to 50 ft tall, the magnificent palm known as the Bismarck palm, Bismarckia nobilis(Hildebrand. & H. Wendl.), has become a popular and successful landscape palm throughout Southwest Florida. Planted as an accent specimen in many landscapes, beautiful silver-blue Bismarck palms have towered over other plantings to the pride of homeowners. However, over the past several years, there has been an increasing amount of Bismarck palms suddenly failing. All of these deaths have been observed in large mature Bismarck palms in the landscape for at least 10 to 12 years and associated with infestations of palmetto weevils, Rhynchophorus cruentatus(Fabricius). Speculations on why these failures occurred have included cryptic cold damage related to several years of below normal winter temperatures, possible nutrient deficiencies or other unknown factors that predisposed these palms to attack by opportunistic palmetto weevils. A brief observational study of some of these failures, both in Charlotte County and in surrounding counties, provided an overview of possible factors and variables that attributed to an abnormally significant rash of Bismarck palm deaths.