The Lemon Cypress (Cupressus macrocarpa ‘Goldcrest Wilma’) is a conifer valued for its bright, golden-yellow foliage and citrusy fragrance, making it a popular accent indoors and outdoors. When the foliage begins to turn brown, it signals a stress response. Identifying the precise cause of this discoloration is the first step toward restoring the plant’s health.
Errors in Watering and Soil Moisture
Watering inconsistencies are the primary cause of browning in Lemon Cypress. Underwatering leads to desiccation, causing the scale-like needles to dry out and turn crispy, often starting at the branch tips. This plant, especially in a container, does not tolerate the soil drying out completely.
Overwatering is a more common problem, suffocating the roots by displacing oxygen in the soil. This lack of air causes the roots to die, preventing water absorption even when the soil is wet. Overwatering symptoms mimic drought, often starting as browning on the lower or inner branches. Prevention requires using a well-draining soil mix and a pot with adequate drainage holes.
The Impact of Light and Temperature
The Lemon Cypress requires bright conditions to maintain its dense, golden color, needing at least six hours of strong light daily. Insufficient light causes the foliage to thin out and the color to become duller. Conversely, moving an indoor plant suddenly into intense, direct afternoon sun can lead to scorching, appearing as bleached or brown patches.
These conifers prefer cooler, moist air, thriving in indoor temperatures ideally between 50°F and 70°F. Low indoor humidity, especially during winter when heating is active, is a significant environmental stressor that leads to needle browning and drop. Placing the plant near heat sources or in the path of cold drafts also causes rapid desiccation and browning.
Pests and Pathogens That Cause Damage
Browning can be a biological issue caused by pests or fungal pathogens. Spider mites are the most common pest, thriving in dry, low-humidity environments. These arachnids feed on plant cells, causing stippling and browning of the foliage. A silky webbing between the needles is a telltale sign of a severe infestation. Scale and aphids are secondary pests that target new growth and sap the plant’s vitality.
Chronic overwatering leads to fungal diseases like root rot, often caused by water molds such as Phytophthora. This pathogen attacks the compromised root system, turning the roots soft and mushy. The resulting foliage browning indicates the irreversible death of those roots.
Steps to Revive Your Lemon Cypress
Once the source of browning is identified, the first step is pruning. Foliage that has turned completely brown will not revert to its gold color, so use sharp, clean shears to remove the dead growth back to healthy tissue. If watering issues are diagnosed, adjust your routine so the top inch or two of soil dries slightly before watering deeply again.
For suspected root rot, carefully remove the plant to inspect the roots. If they are dark and soft, trim away the affected material and repot into a smaller container with fresh, fast-draining soil. Increasing humidity with a pebble tray or humidifier helps mitigate environmental stress. Spider mites require repeated applications of insecticidal soap or neem oil, ensuring thorough coverage.