Gardenias have a well-earned reputation for being difficult specimens for even the experienced indoor gardener. They are usually in great shape when selected at the local greenhouse, where growing conditions closely match this plant’s needs. Bright light, high humidity, and an even supply of moisture and nutrients bring out the best in gardenias. Its glossy leaves and heavenly scented blooms just about cause the plant to leap into your arms, whether it’s a gift for yourself or a loved one.
But then the plant enters the home environment, where hot, dry air and gloomy winter days send the gardenia into a downward spiral. Those delicate flower buds, so filled with promise of good things to come, begin dropping from the plant in droves. The glossy leaves turn dull, yellow, and they too begin to drop like tree leaves in autumn. If the plant survives this cruel change in environment, mealy bugs, spider mites, scale insects and stem cankers provide further challenges to overcome.
Now, for the good news. Gardenias can be successfully grown in the home, but they won’t tolerate neglect like so many other houseplants. Gardenias are native to China and Japan, but also grow well as an evergreen shrub in the south and west coastal areas of the United States. There, the plant reaches up to 6 feet tall!
Your challenge in growing the gardenia indoors is to match the plant’s native environment as closely as possible. First, make sure you give the plant plenty of bright light, preferably direct sunshine, for at least half a day. Winter will likely be the most difficult time to keep high light intensity due to short, gloomy days. Moving plants closer to southern-exposure windows and/or supplementing with plant grow lights will help.
Gardenias thrive in moderately humid air, but maintaining proper relative humidity is a challenge, particularly during the winter heating season. There are several ways to help increase humidity, including running a humidifier and grouping plants together on trays of wet pebbles. Misting by hand with a spray bottle offers only momentary relief and does not really increase humidity in a meaningful way.
A healthy, blooming gardenia will need to be nurtured with a steady supply of water and nutrients, but don’t overdo. The goal is to provide the proper balance of water, air and nutrients. If soils are kept constantly wet, the roots can be starved for air. Too much fertilizer can lead to damaging salt accumulation. Monitor the soil frequently for moisture content, and water thoroughly as the top inch of soil dries. Use a fertilizer formulated for acid-loving, blooming plants, such as an azalea-type product, according to rates listed on the label.
Don’t be afraid to prune the gardenia. In fact, blooming will be more prolific on younger growth. Remember that the gardenia is a woody shrub in its native environment and may need to have older, woody stems removed to make way for new branches. Keep a pair of hand pruners indoors to keep the gardenia rejuvenated.
Keep an eye out for insect pests. If caught early, they can be controlled with insecticidal soaps or other products that are specifically labeled for use on indoor plants. A cotton swab dabbed in rubbing alcohol also will help control a small pest population. You may feel overwhelmed just thinking about all of these responsibilities. However, if you persevere, the gardenia will reward you with masses of stunning white blossoms accompanied by an elegant fragrance that simply cannot be matched by other plants.