Syzygium aromaticum aka Clove

Syzygium aromaticum, or clove, belongs to the myrtle family, Myrtaceae. This evergreen tree comes from the Maluku Islands of eastern Indonesia. Growers raise it across the tropics for spice and oil. Its use as a spice spans at least 2,500 years. The cloves used in cooking are its dried, unopened flower buds.

In gardens, trees reach 15–30 feet [4.6–9.1 metres] tall. Their dense, pyramid-shaped crowns spread 10–20 feet [3–6.1 metres]. Some accounts give a greater height of 66 feet [20 metres]. The tree has a short trunk and glossy, leathery leaves. Each leaf has an oval to lance-shaped outline. The foliage has a scent and stays green year-round.

Flower clusters form at the ends of branches. Each flower has a tube-shaped calyx beneath its petals. This calyx changes from pale green to pinkish red. Fine stamens and a style rise above it. The blooms add scent and colour to the garden. Bees visit the flowers, and the tree is self-fertile. Flowering is seasonal, with no fixed months given. Oval fruits follow, each holding one seed. They turn from red to dark purple-black as they ripen.

Clove needs heat and humid air to grow well. It suits outdoor planting in USDA zones 11–12. In colder regions, growers can keep it in greenhouses. Give it full sun or some shade. Young trees benefit from extra shade while they establish. Deep, fertile loam should drain well but stay evenly moist. The tree also grows in sandy, acid loam near coasts. Dry spells can promote bloom, but drought stress harms growth. Seeds lose viability fast, so sow them fresh. Softwood cuttings offer another way to raise new plants.

The tree serves as a specimen in tropical gardens. Its scented leaves, flowers and dark fruits provide interest. Dried buds flavour baked foods, sweets, meats and drinks. The fruit pulp is also edible. Oil from buds and leaves supplies food flavourings and perfumes. Dried cloves also go into scented mixes and pomanders. Traditional medicine uses cloves for toothache and digestive complaints. These uses do not establish their safety as treatments. Useful Tropical Plants lists no known hazards for the species. Eucalyptus canker and Sumatra disease can affect the tree. Scale insects and mealybugs may also cause trouble. A stem borer is a major pest in parts of India.