Is there anything more romantic than a spring stroll through a moonlit garden filled with the heady fragrance of gardenia, the pure white blossoms shining in the landscape? 

Gardenias are native to China and Japan but are named after Alexander Garden, a botanist who lived in Charleston, South Carolina, in the late 1700s. There are many varieties —  some grow into small trees while others barely get 6 inches off the ground. Gardenias are evergreen with some having small narrow lanceolate leaves and others with large, shiny, broad leaves more than 4 inches long. Some even have variegated crinkly leaves and others have leaves of a golden hue.

The blossoms range from single flowers about three-quarters of an inch across to massive double flowers about 5 inches in diameter. Some varieties have flowers that turn from white to golden yellow as they age.

All gardenias have a few things in common. One is their unforgettable fragrance. Gene Bussell in Southern Living described it thusly: “Sultry as a summer evening and as intoxicating as an exotic perfume, the scent of gardenias settles like a memory onto your soul.” Gardenias are a favorite for wedding ceremonies with their elegant, white blossoms and pleasant romantic fragrance.

They also need similar conditions to flourish. Gardenias do best in moist, well-drained soil, high in organic matter and low in pH. A pH of 4.5 to 6.0 is preferred. With most soils in the greater New Orleans area, the pH will be closer to 7.0 and higher. Incorporating sulfur or aluminum sulfate into the soil prior to planting or around established plants will help.

The soil must be well-drained; gardenias do not tolerate wet feet. They will grow in sun to partial shade but prefer morning sun and afternoon shade. Fertilize in the spring and again about six weeks later with a balanced fertilizer formulated especially for acid-loving plants. Leaf yellowing, or chlorosis, is not uncommon in gardenias, usually as a result of low iron. This can be due to high soil pH or lack of available iron. Adding iron to the soil or spraying with a chelated iron will often solve the problem.

The most common insect problems are the piercing/sucking insects like aphids and whiteflies. These can be controlled using a horticultural oil or insecticidal soap.

Gardenias will usually flower lavishly in spring, and some varieties will bloom again periodically throughout the summer. Prune only to maintain size and shape, and always after the big spring blooming period but before the end of August. Gardenias set spring buds in late summer, and late pruning can reduce next year’s flower production.

Enjoy the exotic fragrance of gardenia while it lasts. Give yours a little care, and they will bless you with years of romantic, moonlit strolls.

For a free subscription to the GNOGardening newsletter, email GNOGardening@agcenter.lsu.edu. It is packed full of timely articles of local interest and information on planting times, monthly chore list and local aggie happenings. You can also visit the LSU AgCenter website for loads of other free information. Send your gardening questions to GNOGardening@AgCenter.LSU.edu.

Q: I prefer to avoid using chemical insecticides on my tomatoes. Will planting marigolds between the plants keep insects away? — Harrison

A: While planting marigolds between your tomato plants may make the garden more beautiful, they will not keep insects off your tomatoes. When studied in controlled experiments, this type of companion planting has been shown to be ineffective. There are organic alternatives to consider, such as Bt, Neem oil, insecticidal soaps and Spinosad.


Joe Willis and Anna Timmerman are LSU AgCenter agents. Email gnogardening@agcenter.lsu.edu with questions or to receive the GNO Gardening Newsletter. For more information, visit lsuagcenter.com.