Canary Island date palms (Phoenix canariensis), also known as pineapple palms, make ideal specimens for large landscapes and beds in the South and West. They grow well in U.S. Department of Agriculture plant hardiness zones 9 through 11, particularly the more arid and semi-arid regions of these zones. These stately palm trees can reach 40 to 60 feet tall, making them too large for many home landscapes. Although tolerant of many soils and environmental factors, they are susceptible to a wide range of pests and diseases. The California Invasive Plant Council notes the species has escaped cultivation in parts of Southern California and taken root along stream corridors, some orchards and a few landscaped areas.
Pineapple palms require a full-sun site with well-draining soil. These trees will grow on clay, loam or sand soils as long as it is moist, never overly wet. Pineapple palms have a moderate tolerance for salt and high drought tolerance, making them ideal in semi-arid coastal regions. Although they are too large for many landscapes, young pineapple palms can do quite well in large containers for several years, making them ideal specimens for a patio. This species is highly susceptible to potassium and magnesium deficiency. The University of Florida IFAS Extension recommends applying 1 1/2 pounds of 8-2-12-4 fertilizer per 100 square feet of canopy area three times per year.
Pruning Pineapple Palms
Pruning these palms is done as much for safety as it is for aesthetics. The tree does not shed its dead fronds, meaning you must remove them. The dead fronds are weakly attached to the tree and may become hazards; falling fronds can injure people, property or animals. To remove dead or dying fronds, cut them with a small chain saw or hand saw near the base without cutting into living trunk tissue. Cut fronds that are growing below the horizontal line (those that are growing at a downward angle). Never cut healthy fronds that are growing horizontal or upward.
Pineapple palms are particularly vulnerable to palmetto weevils (Rhynchophorus cruentatus). Adults lay their eggs in the petiole base of older leaves; young larvae begin to burrow into the tree, which causes stress and, eventually, death. These large weevils grow up to approximately 1 1/4 inches long. Silky cane weevils (Metamasius hemipterus) also attack pineapple palms, although they don't cause significant damage. Unfortunately, however, the holes created by the silky cane weevils can attract the more deadly palmetto weevils. Remove and destroy infested trees to prevent the spread of adult weevils to other palms. Unfortunately, the symptoms aren't easily recognizable until lethal damage is done. Proper pruning and reducing other injury to the leaf petioles can help prevent lethal infestations.
Pineapple palms are particularly susceptible to fusarium wilt, pink rot and sudden crown drop. Fusarium wilt is almost always fatal for these palms. To avoid this disease, do not over-water and avoid planting around the base of the palms. When pruning, disinfect pruning equipment for 10 minutes in household disinfectant or heat the pruning blades for 10 seconds on each side with a butane torch. Remove and destroy infected trees as soon as possible. Pink rot and sudden crown drop are preventable by maintaining healthy, stress-free palms. Correcting stressors, including improper pruning, trunk injuries or irrigation issues, can help reverse the symptoms of both diseases. Graphiola leaf spot, another fungal disease, is mostly cosmetic and causes spotting on the oldest leaves of the tree. Ganoderma fungus forms a conk on the tree; remove the conk to prevent spread. Trunk rots and yellowing are also common to these trees; lethal yellowing causes premature death of old leaves and the loss of fruit and flowers.