Gardenia

Classic Tropical Beauty: Gardenia

      by Tara A. Spears

It’s easy to fall in love with the gardenia, the queen of fragrant flowers. The gardenia flower’s elegant form, brilliant white color, and exotic fragrance have made this plant treasured for centuries. This beautiful perennial shrub produces a plethora of heavily scented white rose-shape flowers throughout the year in southern latitudes making it an excellent choice for a Riviera Nayarit garden. Even when it’s not blooming, the glossy green foliage is attractive.

The dense leaves make it a great choice for privacy hedges or as an edging for a patio or deck. Because gardenias like warm days and cool nights, it will bloom throughout the year providing one of the most easily recognized and treasured fragrances- a fragrance that becomes spicier as the gardenia blossoms age.

Prized for Centuries: The gorgeous gardenia has been cultivated for more than a 1,000 years in China, where it originated. In the mid 1700s the genus was named by horticulturist Carl Linaeus after Dr. Alexander Garden, a Scottish born American naturalist. Its 142 subspecies are part of the flowering plants in the coffee family Rubiaceae, which are native to the humid tropical and subtropical regions around the world. During the colonial period when explorers brought Asian finds to Europe and North American, the exotic gardenia became hugely popular. In the 1920s, due to its unique wax-like beauty and poignant fragrance, gardenias became highly sought after as a cut flower for corsages and arrangements.

Sometimes Difficult: The lovely gardenia has a bad reputation for being finicky when gardeners try to grow it as a house plant outside of the plant’s natural distribution area. When I lived in northern latitudes I grew gardenia as an indoor plant during the winter months-yes, it was a lot of work due to the conditions of a typical centrally heated home and the type of weakened sunlight of that growing zone. The gardenia plant demands high humidity and bright light with 70 degrees (23C) daytime temperatures and nighttime above 60 degrees. (16C) It absolutely cannot tolerate cold. However, when growing gardenias in zone 10 or farther south, it is no more difficult than any other plant when planted in a spot that has acidic soil, good ventilation, correct sunlight, and humidity-all of which is readily available in Mexico.

Take Care When Planting Outside

Be sure to plant your gardenia in well-draining soil conditioned with peat moss and organic matter. The plant will often develop yellow leaves if the soil isn’t acidic enough. To plant, dig a hole twice the size of the gardenia’s root ball and just as deep as the container. When you place the plant into the hole, be sure that the top of the root ball is slightly above the soil’s surface. Mound a mixture of native soil and peat moss around the plant and tamp down to eliminate air pockets. Water thoroughly and keep well-watered, at least a minimum of twice a week, during the growing season.

Because gardenias are primarily grown for their fragrant blossom and handsome foliage, plant gardenias in a location with good air circulation and near patios or windows, where the fragrance can be enjoyed and the flower and foliage observed. Outdoors the gardenia can grow from 6 – 8′ (2-3 meters tall) but is more commonly seen at half that height. You can prune your gardenia to shape and this is best done during the winter months when the plant is semi-dormant. Pruning should be done just after the plant finishes blooming. Pruning should be early enough to allow new growth to be at least 4 – 6 inches long (10-15 cm) by October 1. Gardenias are not salt tolerant, so planting along coastal areas is tricky- I live close to the ocean and mine does fine because I have it planted where it is protected from salty dew, and I add fresh soil twice a year to counteract the salt build up.

All gardenia blossoms possess a wax-like appearance and can be either single or double, depending on the cultivar. Faded blossoms are followed by the appearance of a large, yellowish-red, bitter-tasting berry. I deadhead religiously so I never get berries. To achieve maximum flowering, plant gardenias in full sun or light shade in an open flower bed away from house foundations, pools and walkways. Because gardenias are “acid-loving” plants, they should not be planted near concrete, where soil alkalinity almost guarantees a gardenia will have nutritional problems. In spite of this advice, mine is planted near concrete but I continually amend the soil so it thrives.

The proper fertilization is important for gardenia growth and flower production. Most established gardenias grow well with three applications per year: September, February, June. Plant your gardenias in an area that gets full sun in the morning or filtered light all day. Overheating causes flower buds to drop off before they can bloom- a common occurrence in the Riviera Nayarit. Nighttime temperatures must be in the 60s F (above 15 C) for new flower buds to form. During the dry season, it helps to increase the humidity gardenias love by misting the plant early in the day. Keep the soil moist, but not wet to avoid root rot.

To achieve maximum flowering, plant gardenias in full sun or light shade in an open flower bed away from house foundations, pools and walkways. Because gardenias are “acid-loving” plants, they should not be planted near concrete, where soil alkalinity almost guarantees a gardenia will have nutritional problems. In spite of this advice, mine is planted near concrete but I continually amend the soil so it thrives. The proper fertilization is important for gardenia growth and flower production. Most established gardenias grow well with three applications per year: September, February, June. Plant your gardenias in an area that gets full sun in the morning or filtered light all day. Overheating causes flower buds to drop off before they can bloom- a common occurrence in the Riviera Nayarit. Nighttime temperatures must be in the 60s F (above 15 C) for new flower buds to form. During the dry season, it helps to increase the humidity gardenias love by misting the plant early in the day. Keep the soil moist, but not wet to avoid root rot.

Growing gardenias close to the house enables you to enjoy its fragrance indoors. If you wish to cut some blooms for indoor display, float the blossom in a bowl of water, as the fragile stems do not take up water well.

Starting your own gardenia plants is best done by cutting. Cuttings can be taken any time during the year, but are most successful in June, July, and August. Tip or midsection cuttings with young wood six to eight weeks old should be cut 4 – 5 inches (10-15 cm) long with at least two or three sets of leaves. Cuttings can be taken at or between nodes as they root from the cut end. Leaf removal is unnecessary and undesirable because it results in a longer rooting period. Since established gardenia plants are so reasonable here in Mexico (less than 30 pesos) I don’t take the time to propagate any more.

Applying mulch to your gardenia is very important in the tropics with the long dry season as mulch helps with moisture retention. A good mulch to use is pine needles or other organic matter. Provide a mulch covering that is two inches thick and do not allow the mulch to touch the trunk of the gardenia bush. I use landscape cloth and lava rock in my Mexican garden-both materials are available at Home Depot. CAUTION: do NOT use wood bark or grass clippings as mulch in this humid subtropical area! When I first moved to south Florida and put in numerous flower beds, I immediately purchased a truck-load of bark nuggets to mulch the plants, because that’s the standard procedure in northern latitudes. Within a few months of subtropical temps and high humidity, I had a yard infested with termites, carpenter ants, and fire ants. I had to rake up and haul away all the bark and hire professional pest exterminator to eliminate the insects before they invaded my house- a very costly mistake. I then switched to using bagged rocks for mulch: it protects the plant roots, helps retain moisture, and looks manicured while reducing weeds without creating habitat for harmful insects. In addition to the listed insects, in the Riviera Nayarit the wrong type of mulch will also attract scorpions.

Another reason for gardenia’s difficult to grow reputation is it’s propensity to attract damaging insects. Mealybugs, aphids, scales and whiteflies are all problematic on gardenias. Mealybugs are one of the most prevalent gardenia pests and are easily identified as white, cottony masses found in the leaf axils and other protected areas of the plant. Aphids can also be challenging on gardenias. Be on the lookout for a soft-bodied, tear-shaped insect, typically clustered around newer growth and/or on the underside of leaves. Another pest on gardenia is scale which appears as raised brown bumps on the stems and underside of leaves. Whiteflies are tiny pests that can become a big problem on gardenias. Whiteflies are small winged insects which look more like moths than flies. Whiteflies can be prolific and seem to come out of nowhere in what appears to be an instant snowstorm of minute dust-like particles. Not only does whitefly feeding damage plants, whiteflies can also transmit plant viruses. Inspect your plants regularly and apply control measures immediately when pests appear. I have a bigger problem with the pests during the dry season. Each of these insects can be washed off the leaves with a water/soap/garlic juice mixture.

While gardenias might be picky about their care, if you’re patient and remember the basics, your efforts will be rewarded. A beautiful blooming gardenia is worth it.