April 6, 2002

Question: We have several pine trees around our home property and it is a time consuming problem picking up several barrels of these large cones that have the size to shatter lawnmower cutting blades. Recently, I heard that female pine trees do not have pine cones or not many on a given tree as the male tree. Could you comment on this?

- Bruce, Pine Island

Answer: Fruit and seed production are the results of plants engaging in sexual activities known as pollination. Depending on plant species, some flowers on a plant only produce pollens and are known as male flowers. Other flowers, when pollinated, produce fruits and cones and are known as female flowers. To complicate matters, some plant species have male and female flowers confined to separate plants. When this occurs, the species is known to have male and female plants. Although both male and female plants will flower, only the female plant produce fruits. Examples of species having male and female plants include mahogany, southern magnolia and the Canary Island date palm. Dioecious is the term we give to a species with separate male and female plants. The most common occurrences, however, are trees with both male and female flowers on the same plant. In these cases, the species is self-fruitful. All plants, of these monoecious species, will bear fruits or cones. Monoecious trees include slash pines, common throughout south Florida, black olives, oaks, and crape myrtles. Your pine trees are monoecious and cannot be separated into male and female trees. Your problem will continue unless selected trees are removed.