The black olive tree (Bucida buceras) is a popular evergreen choice for landscaping, valued for its dense canopy and ornamental appeal. Native to tropical regions like the Caribbean and Central and South America, it’s often called the “Shady Lady” for the shade it provides. Despite its common name, it is not related to the edible olive tree and does not produce edible fruit.
Identifying Black Olive Tree Leaves
Black olive tree leaves are typically dark bluish-green with a leathery texture. They are generally small, 2 to 4 inches long, and cluster at branch tips. Their shape can be oval, spatulate, obovate, or oblanceolate, with an entire margin.
Though evergreen, black olive trees naturally shed some leaves, especially during new growth or environmental changes. This natural shedding is distinct from problem-related leaf loss, and new leaves usually regrow. Young trees may also have small spines mixed among the leaves on the branches.
Common Leaf Problems and Solutions
Black olive tree leaves can exhibit symptoms of environmental stress, nutrient deficiencies, or pest infestations. Black spots often indicate fungal infections like olive leaf spot, creating dark lesions that can lead to yellowing and premature leaf drop.
Yellowing leaves (chlorosis) may stem from nutrient deficiencies or improper watering. Overwatering can cause root rot, leading to wilting and yellowing.
Sap-sucking pests like scale insects or aphids also cause leaf discoloration and distortion. To address these, ensure proper soil drainage and adequate watering. Improve air circulation through pruning and use appropriate fungicides for fungal spots. A balanced fertilizer can also enhance the tree’s resilience.
Managing Leaf Litter and Sap
Black olive trees are known for producing leaf litter and secreting sap, which can be practical concerns. The tree naturally sheds leaves, contributing to leaf litter. Additionally, the tree produces small, black, inedible seed capsules that resemble olives, which can also fall and stain surfaces due to their tannic acid content.
The sap issue is typically caused by honeydew, a sticky excretion from sap-sucking insects like aphids, whiteflies, mealybugs, and scale insects. This honeydew creates a sugary film on leaves and other surfaces, which then becomes a breeding ground for sooty mold, a black, soot-like fungus. Sooty mold itself does not directly harm the plant but can block sunlight, hindering photosynthesis.
Managing these issues involves regular cleaning of surfaces beneath the tree and addressing the pest population. A strong jet of water can help remove both honeydew and sooty mold from leaves. For more persistent sooty mold, a mild soap solution can be applied, followed by rinsing. Pruning low-hanging branches can also reduce access for ants, which protect honeydew-producing pests.
Are Black Olive Tree Leaves Toxic?
The black olive tree (Bucida buceras) is generally considered non-toxic. While the tree produces small, black, olive-like fruits, these are not edible. Reputable sources, including the ASPCA, do not list Bucida buceras as toxic to humans or common pets.
Despite being non-toxic, ingestion of any plant material by pets can potentially cause mild gastrointestinal upset. If a pet ingests a large quantity of any plant, or if unusual symptoms are observed, consulting a veterinarian is advisable. The primary concern with black olive trees is typically the mess from falling fruit and honeydew, rather than toxicity.