In a zone 6 garden, gardenias can be treated as annuals and just enjoy them during the summer months. If they are in containers, you can bring them in for the winter and keep in a room that has good light and not too warm. Gardenias do best in the garden with good soil that has been amended with compost. Use a fertilizer for acid-loving plants such as azaleas in June. Avoid watering the leaves, just water at the base of the gardenias. And, don’t let them dry out.
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