The Ginkgo biloba, often called the maidenhair tree, is one of the oldest living tree species on Earth, earning it the title of “living fossil.” Its unique fan-shaped leaves and brilliant golden fall color make it a popular landscape choice worldwide. Although celebrated for its remarkable hardiness and resilience to pollution and environmental stresses, the Ginkgo is not entirely immune to problems. Distress usually occurs when specific cultural or environmental needs are unmet. Understanding these common issues is key to maintaining a healthy specimen.
Environmental Stress and Deficiency Issues
In the first few years after planting, slow growth is common due to transplant shock. To help the tree establish, keep the root ball consistently moist but not waterlogged. Avoid heavy fertilization, which can discourage root expansion. Once established, the Ginkgo tolerates drought, but extreme dryness can cause leaf scorch or premature leaf drop.
Overwatering or planting in poorly drained soil causes water stress, leading to yellowing leaves and decline. Ginkgos do not tolerate consistently soggy ground, which quickly causes root problems. Proper site selection in loose, well-drained soil is the best preventative measure.
A common visual problem is chlorosis, where leaves turn yellow while the veins remain green, indicating a nutrient deficiency. This condition often occurs in highly alkaline soils. A high pH level chemically locks up micronutrients like iron and manganese, preventing the tree from absorbing these essential elements even if they are present in the soil.
To address alkaline-induced chlorosis, perform a professional soil test to confirm pH and nutrient availability. Short-term solutions include applying chelated iron products or using foliar sprays for a quick response. For lasting correction, the soil pH can be slowly lowered with amendments like elemental sulfur or ferrous sulfate.
Biological Threats: Pests and Diseases
The Ginkgo is highly resistant to most insect pests and diseases, a trait linked to its ancient history. When biological issues appear, they are usually minor and rarely threaten the tree’s health. The most common insect threats are sap-suckers, such as aphids and scale, which colonize tender new growth.
Aphids feed on leaf tissues, causing distortion and excreting honeydew. Infestations are often managed by targeted blasts of water or by applying horticultural oil or insecticidal soap. Chemical pesticides are seldom necessary due to the mild nature of most infestations.
Fungal issues are typically secondary problems resulting from poor environmental conditions. Leaf spots or blight appear as brown or black spots, often encouraged by high humidity or consistent overhead watering. Improving air circulation around the canopy and ensuring excellent soil drainage are effective cultural controls. Root rot is a more serious fungal disease attacking trees in constantly saturated soil, emphasizing the need to avoid overwatering and compacted sites.
Mitigating Location and Maturity Challenges
A major challenge with mature Ginkgos is the foul-smelling fruit produced by female trees. Ginkgos are dioecious, meaning they are either male (pollen) or female (seeds). The fleshy seed covering contains butyric acid, which releases a strong odor similar to rancid butter when the fruit falls and decomposes.
To avoid this nuisance, plant only male cultivars, which are propagated asexually and guaranteed not to produce fruit. Named male varieties like ‘Autumn Gold’ or ‘Princeton Sentry’ are preferred for urban planting. Since female trees may take 15 to 20 years to begin fruiting, the problem is often discovered too late. For existing female trees, fruit-eliminator sprays can be applied in spring, but this requires precise timing and is difficult on large trees.
While Ginkgos are generally deep-rooted, their roots can become aggressive when constrained in compacted urban soil. Proper initial placement away from foundations, sidewalks, and utility lines is essential to prevent structural damage. The tree’s natural upright form can lead to weak branch attachments or co-dominant leaders. Early structural pruning is necessary to establish a single, strong central leader and wide, well-spaced branches. This preventative pruning reduces the risk of limb breakage from heavy ice or wind loads.