Care for Gardenia Shrubs

Grow gardenia shrubs in well-draining, slightly acidic soils with pH range between 5.5 and 6.5 and full sunlight to partial shade exposure. Provide the shrubs consistent daytime temperature between 68 and 75 degrees Fahrenheit, and nighttime temperatures between 60 and 65 degrees F.

Water gardenias every week so the soil is evenly moist at all times. Insert your finger 2 inches into the soil and irrigate if it feels dry. Increase the frequency of irrigation during dry periods to reduce stress on the shrub. Avoid overhead watering, which increases the chances of fungal diseases; provide a slow stream of water to the plant at soil level.

Mulch the soil around gardenias with wood chips, shredded bark or dried grass clippings to help retain soil moisture and keep the roots cool. Keep the layer of mulch 2 to 3 inches thick starting 6 inches from the trunk to prevent rot.

Spread 1/2 lb. of 15-5-10 fertilizer per 100-square-foot area in spring. Repeat fertilizer application when the shrubs flower and again after flowering. Do not feed gardenias in fall.

Clip off old, damaged and diseased stems and blooms on the shrub to maintain its appearance and invigorate growth. Remove old branches from within the canopy to improve sunlight penetration. Use sharp, sterilized pruning shears to prevent chances of disease. Collect clippings and discard.

Inspect the gardenia shrub for common pests such as aphids, spider mites, mealybugs and scale. Wipe infested parts with cotton soaked in rubbing alcohol to control spread. Treat large infestations with low-toxicity insecticide, according to manufacturer’s directions. Treat common diseases such as leaf spot, sooty mold, powdery mildew and canker with a registered fungicide.