Although there are some 400 species in the genus Ixora, only a handful are commonly cultivated, and the common name, ixora, is usually used for I. coccinea. Ixora is a dense, multi-branched evergreen shrub, commonly 4-6 ft (1.2-2 m) in height, but capable of reaching up to 12 ft (3.6 m) high. Ixora has a rounded form, with a spread that may exceed its height. The glossy, leathery, oblong leaves are about 4 in (10 cm) long, with entire margins, and are carried in opposite pairs or whorled on the stems. Small tubular, scarlet flowers in dense rounded clusters 2-5 in (5-13 cm) across are produced almost all year long. There are numerous named cultivars differing in flower color (yellow, pink, orange) and plant size. Several popular cultivars are dwarfs, usually staying under 3 ft (1 m) in height. Ixora 'Nora Grant' is a popular dwarf and 'Super King' is a popular hybrid with much larger flower clusters than the species.
Ixora coccinea is native to tropical southeast Asia, including southern India and Sri Lanka. It has become one of the most popular flowering shrubs in South Florida gardens and landscapes.
Ixora is moderately salt tolerant, but not at all tolerant of alkaline soils, which will cause the leaves to become chlorotic (yellowish). Don't plant ixora where it will get runoff from concrete or stucco. Do plant in acidic soil, feed with a high nitrogen fertilizer and mulch well.
Light: Ixora does well in partial shade in the warmest areas. It does best, however, with full sun most of the day, but some shade during the hottest hours. Plants in more sun will be denser and more compact, and produce more flowers.
Moisture: Ixora likes high humidity and a moist, friable, well drained soil that is high in organics. During warm weather they should be watered regularly. Water sparingly in winter.
Hardiness: If temperatures dip into the thirties F (5 or below C), leaves and small twigs will be damaged. Light freezes may kill the plant to the ground, but it usually sprouts back in spring.
Propagation: Propagate ixora from young fast growing tip cutting in spring or summer. Bottom heat improves chances for success.
Ixora is used in warm climates for hedges and screens, foundation plantings, massed in flowering beds, or grown as a specimen shrub or small tree. In cooler climes, ixora is grown in a greenhouse or as a potted house plant requiring bright light. Ixora is also grown in containers, looking very distinguished as a patio or poolside plant. This tight, compact shrub is much branched and tolerates hard pruning, making it ideal for formal hedges, although we think it is at its best when not sheared.