This article was originally produced as a bi-monthly news column for the Vero Beach Press Journal

 

Date of release: May 16,  2001

Daniel F. Culbert, County Extension Agent

CHOOSE IXORA FOR YEAR-ROUND COLOR

A popular plant in many new local landscapes is Ixora, an ever-blooming shrub that is often unknown to recent residents. It is one of the mainstays of Florida yards that is easy to grow and maintain. Today’s column came from a fact sheet written by former horticulture agent Sylvester Rose, which was updated by University of Florida Extension specialists Ed Gilman and Bijan Dehgan.

Ixora is a tongue twister of a name - it is pronounced "icks-SORE-ah". While some references call this shrub Flame of the Woods, in the nursery trade it is simply called Ixora, which is part of its botanical name, Ixora coccinia. There are several different varieties available, and the names may confuse homeowners trying to identify this plant.

Ixora is closely related to the exotic Gardenia and Florida’s native wild coffee. Despite its common use in our area, this evergreen shrub is a native to southern Asia. The glossy leaves grow across the stems from each other, have a strong midrib that ends in a slight point and have very short leafstalks (petioles).

Full sun allows Ixora to produce the maximum numbers of flower clusters. However, this shrub can tolerate partial shade. It is tolerant to moderate levels of salts in the irrigation water, but plant it away from direct ocean breezes. Avoid sites that are exposed to cold northwest winds. The USDA hardiness rating for this plant is 9B, which means that it is at the northern extreme of its range here on the Treasure coast. Temperatures below freezing will cause leaf damage and a hard freeze will knock it to the ground. This past winter, many local Ixora planted in unprotected sites showed leaf damage and dieback.

Ixora shrubs are best adapted to well drained soils that are slightly acidic. In many of our coastal area’s soils, they develop iron and manganese deficiencies, which will appear as yellowed areas between the green veins. Severely neglected Ixora have almost pure yellow leaves. Temporary relief from these pH induced deficiencies can be treated by applying chelated iron fertilizers. Better results occur when the plant is placed in acidic soils or if copious amounts of organic materials and mulch are added to the planting area. Special acid fertilizers with minor elements made especially for Azaleas, Gardenias and Ixora are recommended if your soil pH is high. Our office can test your soil for pH.

Few pests bother Ixora. If scales and aphids are allowed to build up, black sooty mold will appear on the leaves. Insecticidal soaps can take care of both of these concerns. Occasional nematode damage is reported, and generous use of organic mulches will also reduce the injury from these microscopic soil pests. An occasional visitor to Ixora are the stinging caterpillars; be careful when you are hand pruning that you don’t grab a saddleback by accident.

Ixora are commonly used as foundation plantings and respond well to shearing. Sides of hedges should be tapered to allow light to reach the lower branches. If unpruned, Ixora can reach to twelve feet in height, and would work well as a screening plant.

The red, orange, yellow or pink colored flowers are what makes Ixora a popular landscape plant. Each floret usually has four petals that appear somewhat like a cross. They have a deep tubular throat that may be up to two inches long. Flowers grow in clusters on the ends of stems and appear almost any time of year, but especially in summer. A single flower cluster can last for 6 to eight weeks. At one time Ixora were being considered for use as a potted flowering plant that could be shipped during holidays.

Occasionally the flowers will produce a round berry that matures to a purple black color. They are described as edible, but not very palatable, and can contain seed which is rarely used for growing new plants. The preferred way to grow new Ixora is by stem cuttings, which assures that the desired characteristics will occur on new plants.

Popular cultivars of Ixora include the following:

Ixora 'Maui'  Photo: GCREC/IFAS/UF Two different color forms of Dwarf Ixora ( I. taiwanensis) growing in Guanacaste, Costa Rica.  Photo: Dan Culbert, UF/IFAS   Ixora 'Maui sunset'.  Photo: Tom Murphy

Are you interested in purchasing Ixora for your Florida yard? Look for plants that are very full with multiple branches that will support many blooms. These upright spreading shrubs should be at least half as wide as they are tall. Dwarf Ixora are often sold in one gallon containers; a quality one-gallon dwarf Ixora should measure 9 inches in height and from 4-7 inches wide. Larger cultivars of Ixora should measure 15-18 inches in height, and their branches should spread 12 to 18 inches in width.  High quality Ixora retail for about $10.00 for a three-gallon container; if you find less expensive plants, they are generally of inferior quality.

While other landscape plants have higher maintenance, the Ixora  requires little extra care.  Regular maintenance includes adding a thick layer of NON-cypress mulch, and monitoring  for aphids and scales.  If black sooty mold appears, use an insecticidal soap to keep the pest levels manageable. Minimal irrigation is required, but periodic fertilizers are applied.

Sooty mold on Ixora

Excreted honeydew collects on these Ixora leaves. A black fungus, called sooty mold, soon colonizes the carbohydrate rich honeydew. Photo by Doug Caldwell, UF/IFAS

 

Ixora deficiancy - P & K

These purplish leaf spots on Ixora are due to P and K deficiencies. A cold snap will also enhance the appearance of these symptoms.  Photo by Doug Caldwell, UF/IFAS

Magnesium Deficiency – Photo UF/IFAS.

Ixora - Magnesium defiency 

No, This is not a Croton, but a new planting of Ixora in a Stuart subdivision.  The soil is a marly shelly, fill. Photo by Dan Culbert, UF/IFAS

 

If you need additional information on Ixora, visit your county Master Gardeners, or call or stop by your county Extension office. For those with other questions about Florida Yards, contact me - my phone number is 863-763-6469 and you can send e-mail to indinanco@ufl.edu 

 

References

Caldwell, Doug.  Ixora Shrubs are litmus test for Several Soil Nutrient Problems.  Naples: UF/IFAS Collier County Extension Service, March 2005.  http://collier.ifas.ufl.edu/CommHort/CommHortPubs/Ixora%202002NDN.pdf

Gilman, Ed.  Ixora coccinia [FPS-291]. Gainesville: Florida Cooperative Extension Service, 10/99.  hort.ifas.ufl.edu/database/documents/pdf/shrub_fact_sheets/ixococa.pdf  

Keeler, Gail,  Gabel, Kim  and Schoellhorn, Rick.   Ixora for South Florida [ENH-995].  Gainesville: Florida Cooperative Extension Service, November 2003.  http://edis.ifas.ufl.edu/ep164 

Cultivar photos:  http://www.jaycjayc.com/ixora-species-jungleflame/ 

Return to Dan Culbert's webpage

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-Cahncey, Interim Dean. Last update: 07/05/2011 .  This page is maintained by Dan Culbert  Hit Counter