With their deep green leaves and waxy white blooms, gardenias are a beloved garden staple in mild climates, especially in the southern United States. These hardy plants tolerate heat and humidity, but they can be tricky to grow, especially in cooler climates. Read on to learn about troubleshooting gardenia leaf curl.
Help! My Gardenia’s Leaves are Curling!
If leaves of gardenia are crinkling and wrinkling, there may be several factors at play.
Gardenia Leaf Curl and Spider Mites
Spider mites are often to blame when leaves of gardenia are crinkling. You may not notice the pests because they’re so tiny, but the fine webbing they leave on the foliage is a telltale sign. A gardenia affected by spider mites may also exhibit yellow or spotted leaves.
If you decide spider mites are causing gardenia leaf curl, you can often remove the eggs and mites with a strong stream of water from a garden hose. If that doesn’t work, use a commercial insecticidal soap spray. You may need to spray every few days until the pests are eradicated.
If all else fails, try a systemic insecticide that will be absorbed throughout the plant. Also, be sure to water properly; mites are attracted to dry, dusty conditions.
Curly Gardenia Leaves due to Soil Problems
Gardenias prefer acidic soils with a pH between 5.0 and 6.5. It’s a good idea to test the soil before planting gardenias and to make adjustments if the pH level is too high.
If you’ve already planted gardenias without testing the soil, make adjustments by adding chelated iron, aluminum sulfate or water-soluble sulfur to the soil about 3 feet (1 m.) from the plant. You can also spray the leaves with chelated iron.
Once the plant is looking healthier, feed it regularly, using a slow-release fertilizer for acid-loving plants such as azalea or rhododendron. Continue to test the soil regularly and make adjustments as needed.
Wrinkled Garden Leaves from Improper Watering
Improper watering, either too much or too little, may contribute to a problem with curly gardenia leaves. Gardenias need regular, consistent irrigation, but the soil should never become too wet or too dry.
As a general rule, gardenias need at least 1 inch (2.5 cm.) of water per week, either from irrigation or rainfall. A generous layer of mulch will prevent evaporation and help keep the soil evenly moist.