UF/IFAS Okeechobee County Extension Service

E-mail: dfculbert@ifas.ufl.edu

Here in Florida and through the south, Gardenia bushes make a bold statement to noses and eyes alike that spring has arrived. They can be purchased as a seasonal potted plant, briefly enjoyed, and then relegated to the compost pile. Or with a little extra effort, they can become a regular feature of your landscape if a few basic rules are followed.

Gardenias provide a beautiful fragrance for Florida Yards. Photo: Dan Culbert, UF/IFAS

With care, this evergreen shrub with flawless white flowers and delicious smell can be added to your Florida Yard. Careful placement in the landscape and monitoring of pests will make it a successful landscape specimen.

This plant should be planted in rich acidic soils with adequate moisture and good drainage. Gardenias require more iron than other plants, and in high pH soils, this nutrient will limit the growth. Often soils near walls contain bits of cement, which makes soil pH alkaline, preventing the uptake of iron. The result can be yellowed leaves and fallen flower buds.

Chelated iron fertilizers will be required if your soil is above 7.0. If you don’t know what the soil pH is, bring a small sample (1 cup) of soil to our office for a free pH test. Most garden centers carry fertilizers for acid-loving plants like gardenias, but in our area, choose products that are low in phosphorus. Apply these fertilizers according to the label’s instructions, or contact our office for additional help.

Full sun will be needed for good flower production. Place landscape Gardenias in areas with good air movement. This helps to keep the fragrance from overpowering those that don’t appreciate its odor. It also helps to keep the foliage dry and reduces the number of pests that bother this plant.

This shows the flower of Gardenia thunbergia the common rootstock used for Gardenia plants. Photo: UF/IFAS

A critical choice for choosing landscape Gardenias is to select a plant that is grafted on to Gardenia thunbergia rootstock. Nursery-grown plants that have been produced in this manner will have nematode resistance and the vigor needed to last for several years in the landscape.  Ungrafted plants will be ok as potted houseplants but will not survive for long in your Florida Yard.

  There are several different cultivars of Gardenias available in our area. A listing of these varieties is included in the University of Florida bulletin listed below. Some differences in flowering season exist (early spring to mid summer), flower shape (single  or double flowers), while other Gardenias differ based on plant size (dwarf, medium sized or upright).

The Gardenia is a key plant - known to be attractive to several insect pests - and must be monitored in order that pests don’t escape to other parts of your landscape.  Aphids, scales, whiteflies, and mealy bugs can suck the sap of this plant, and their waste material on the shiny green leaves can be a place for black sooty mold to appear. Use of insecticidal soaps or horticultural oils can keep these pests in check.

Other bothersome Gardenia pests are flower thrips, small linear insects that cause flowers to fade more quickly. Application of chemical insecticides before the flower buds open will keep these pests in check - check our office for current recommendations.

A common complaint with Gardenias is leaf or flower-bud drop. Often this is a result of over or under-watering, cold temperatures, root nematode damage, excessive pest damage or over- fertilization. Providing a good site, and adequate care will insure that Gardenias can provide that strong smell of the south to your Florida Yard.

Our office has references available on the selection and care of Gardenias for your Florida Yard. You may want to visit our Okeechobee Master Gardeners  or on the internet at http://okeechobee.ifas.ufl.edu for additional information on this delightful plant. Our office is located at 458 Hwy 98 North in Okeechobee. Call us (863)763-6469, or send an email to indianco@ifas.ufl.edu if you have questions. Happy Gardening!

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REFERENCES

Bradshaw, Joan and Park Brown,Sydney.  Growing Gardenias in Florida.   Gainesville: Florida Cooperative Extension Service, May 2009. http://edis.ifas.ufl.edu/MG336

Brown, Stephen. Gardenia thunbergia.  Ft. Myers: UF/IFAS Lee County Extension Service, 2007.  http://lee.ifas.ufl.edu/Hort/GardenPubsAZ/Gardenia%20Thunbergia.pdf 

Gilman, Ed. Gardenia jasminoides [Fact Sheet FPS-222]. Gainesville: Florida Cooperative Extension Service, October, 1999. http://hort.ifas.ufl.edu/database/documents/pdf/shrub_fact_sheets/garjasa.pdf   

ibid. Gardenia jasminoides 'Prostrata'  Dwarf Gardenia[FPS-223].  http://edis.ifas.ufl.edu/fp223 

Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin. Florida Cooperative Extension Service / IFAS /University of Florida. Millie Ferrer-Chancy, Interim Dean.  Last update: 04/21/2011 .  This page is maintained by Dan Culbert