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Ixora provides a profusion of blooms

In hanging pots, as bushy pillars, in hedgerows and borders, the bouquet-covered ixora splashes our landscapes with brilliance.

By Yvonne Swanson, Special to the Times
Published October 13, 2007

it takes a truly marvelous green thumb to keep a hydrangea alive in the subtropical climate of the Tampa Bay area, but practically anyone here can grow its tropical look-alike, the bright and prolific bloomer, ixora.

With its pompon cluster of flowers, ixora blooms throughout the year in many shades of bright red, orange, salmon, pink and yellow. There are about 400 species of ixora, but the most common one grown in Florida is the yellowish-orange Ixora coccinea or "Flame of the Woods." Other popular choices include the red "Nora Grant," orange "Maui" and "Singapore Yellow." Less frequently seen are white varieties, including a white "Nora Grant" and "Herrera's White."

A native of India, ixora is a hugely popular shrub used by professional landscapers, and with good reason. Its dark evergreen, glossy leaves and compact habit make ixora ideal for a hedge or border. When grown in the right conditions, its clusters of vibrant flowers, up to 6 inches tall, bloom almost continuously throughout the year.

Ixora blooms best in full sun, but will still flower in light shade. Depending on the cultivar, it typically grows between 3 and 8 feet tall, although some tower well over 10 feet. Dwarf varieties are a better choice for containers or hanging baskets.

Although ixora is easy to grow, it demands just the right soil. Acid is best, with a pH of about 5, according to horticulture experts at the University of Florida. Before planting ixora (or any acid-loving plant), you should know the acidity of your soil. Test kits are available for sale at garden centers, or you can use an inexpensive soil test from many county extension offices.

You can increase the acidity of your soil by adding organic matter, including composted manure, peat moss and compost. Coffee grounds are acidic, so regularly toss those on your planting bed or add them to your compost pile. Pine straw is another good organic source for acid and makes a nice mulch for acid-loving plants. Choose a slow-release acid fertilizer to feed ixora.

If your soil is particularly alkaline (usually the case with beachfront property), you can add an iron sulfate product to planting beds several times each year, although a foliar spray will work best. Never use lime or dolomite near ixora or other acid-loving plants; these products boost soil alkalinity. Signs of too much alkaline and resulting nutritional deficiencies are yellow, chlorotic leaves.

The pH of your yard can differ from one area to another. This is especially true for soil next to concrete foundations, patios and walkways. Concrete is so alkaline that it will alter nearby soil.

You can prune ixora any time of the year, but one good pruning a year is best to promote maximum flowering. If you lightly prune throughout the year, you risk cutting off tiny flower buds and missing the real beauty of this tropical specimen.

If you want to use ixora for a manicured hedge, choose Ixora coccinea ("Flame of the Woods") because it has smaller leaves and flower clusters than other varieties. "Nora Grant" and "Maui," with their 3- to 4-inch leaves and big flower clusters, won't perform well or flower if repeatedly trimmed as hedges.

Occasional pests - among them aphids, scale and mealybugs - can cause black, sooty mold to form on leaves, but you can control the problem by applying a horticultural oil spray weekly for about a month. Soil-borne nematode worms are another concern, so deter them by keeping mulch a few inches away from the trunks of plants.

Yvonne Swanson is a freelance writer in St. Petersburg and a master gardener for Pinellas County.

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FAST FACTS

The acid test: pH

The pH value of soil is a measure of acidity and alkalinity. The scale ranges from 0 to 14. A pH of 7 is neutral; the ideal range for most plants is between 6.5 and 7. Scores lower than 7 are acidic and above 7 are alkaline.

Why is pH important? Plants prefer different pH values, and when grown in the right soil, they are better able to absorb nutrients such as nitrogen, phosphorous and potassium, all essential to plant growth and health. Nutritional deficiencies can be avoided by keeping the soil pH in check.

The best way to achieve a neutral soil is by adding organic matter such as leaves, compost and manure. Non-organics, primarily chemical fertilizers, make soil more acidic.

Products are available at the garden center that will quickly alter soil pH. To increase acidity, add aluminum sulfate or sulfur. To increase alkalinity, use ground limestone or wood ash. Products should be worked into the soil prior to planting.

[Last modified October 11, 2007, 17:19:16]