By Keri Byrum
The sweet smell of gardenias is hard to resist. These old-fashioned flowers are making a comeback thanks to new, tough varieties, as well as increasing interest in adding fragrance in the garden.
Nutrition. Healthy gardenias are deep green; light-pale-green leaves indicate they need more fertilizer. Fertilize two to three times per year to keep your gardenias healthy.
Soil. Use an acid-loving plant fertilizer to help keep the pH low. To uptake nutrients gardenias prefer a pH between 5.0 and 6.5. Gardenias grown close to the foundation of a home often show nutrient deficiencies because the concrete causes a higher pH in the soil. Your county extension office can test your soil's pH.
Pests. The first thing most people see is a black film on leaves. This sooty mold isn't bad, but it indicates your gardenia hosts harmful pests. Now is the time to look for the culprit. The usual suspects are:
- Mealybugs: Most common, these resemble small pieces of white cotton on the stems and backsides of leaves.
- Aphids: Usually you can find these small, pear-shape insects on the tips of new branches.
- Thrips: Newly opened flowers frequently harbor these tiny, narrow insects.
- Scale: Look for raised brown bumps along the stem and underside of leaves.
Pest control. Several options exist for controlling gardenia pests. I prefer a systemic pesticide that protects the plant from a variety of pests for several months. You apply this pesticide in a granular or liquid form at the base of the plant, which takes up the chemical into the leaves to kill any insect feeding on the plant.
During cool weather horticulture oils also offer an option for pest control. Spray the plant thoroughly, getting as best as possible the undersides of leaves and stems. This option includes organic products to kill the pests.
Explore the wide variety of gardenia varieties available for your garden. From small border plants to large shrubs, there is a wonderfully fragrant option for you.
Find out what our 10 regional gardening experts are dealing with these days—pests, viruses, and even beneficial insects.Learn More