Woody > Syzygium > Syzygium aromaticum > Syzygium aromaticum
Syzygium aromaticum
Clove
Origin: The clove tree is native to the Molucca Islands of Eastern Indonesia. Its cultivation has since spread to many other tropical countries.
Mike's
Opinion
"
Syzygium aromaticum is a valuable tree for its interesting characteristics in the landscape and edible and medicinal uses. In our climate this tropical tree can be grown in containers to add spice and aroma to your porch garden. Its bright red flowers are eye-catching and the buds can be harvested and dried for edible uses. Leaves offer varying interest as they emerge pink and mature to dark green. Smooth brown bark compliments large glossy foliage, overall proving to be an attractive specimen. - Rachel Mulder
Michael Pascoe, NDP., ODH., CLT., MSc. (Plant Conservation)
"
| Family |
| Myrtaceae |
| Genus |
| Syzygium |
| Species |
| aromaticum |
| Category |
| Woody |
| Type |
| Tree (evergreen) |
| USDA Hardiness Zone |
| 11b - 12b |
| Canadian Hardiness Zone |
| Requires cold season protection. |
| RHS Hardiness Zone |
| H1c - H1b |
| Temperature (°C) |
| 7 - 16 |
| Temperature (°F) |
| 45 - 60 |
| Height |
| 7 - 18 m |
| Spread |
| 2 - 6 m |
Photographs
Cultivars
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Description and Growing Information
Flowering Period
| General Description |
| It is a broadleaf evergreen that commonly grows in tropical climates such as Indonesia, Sri Lanka, Pakistan, India, Tanzania, and Madagascar. It has dense glossy foliage and bright red flowers. Well known around the world for its flower buds, which are harvested and dried as a spice. This tree is slow growing and has a long-life span. |
| Landscape |
| Cloves are mostly grown in commercial plantations, however in the landscape they serve well planted as an understory specimen in protected locations. They are typically featured in edible and Asian gardens and can reach over 100 years old in the right conditions. In colder climates they are grown in containers and brought inside for the winter. Many growers harvest and dry their own buds. They should be planted away from paths and roadways as they are not pollution tolerant. |
| Cultivation |
| They prefer full sun to partial shade and grow best in well-draining, acidic, loam or sandy soil, located in a humid environment. Climates with dry periods are ideal for flowering but as these trees are easily stressed, they must have deep enough roots and fertile soil to receive enough water. In the landscape, they will need to be irrigated and will not survive changing seasons. |
| Shape |
| Large and upright, with a slow growth habit, they have a bushy appearance due to their many short branches and long leaves. |
| ID Characteristic |
| Many plants in the Myrtaceae family are strongly aromatic. The most interesting identification feature of this tree is the distinctive clove-like aroma from its flowers, leaves, and stem due to its many oil glands. Another way to identify them is by their large, glossy elliptical leaves arranged oppositely on the branches. They also have small flower panicles that are noticeably red. |
| Pests |
| Clove trees are susceptible to several pests. Eucalyptus Canker is a fungal disease that enters the tree through open wounds and causes limb dieback, this can become a common occurrence if proper pruning is not practised. Sumatra Disease is a bacterial disease leading to death within 3 years of infection, it causes dieback beginning in the crown of the tree. Leaves become chlorotic, fall off and discoloration of vascular tissues shows up as grey streaks in new wood. There is no cure, however oxytetracycline may be injected to slow tree decline. Pesticides are available to control vectors of this disease, which are believed to be Hindola striata and Hindola fulva. Common insects that affect clove trees include Coconut Scale which severely damages the leaves, Oriental Fruit Fly which eats the fruit, and Soft Scale which damages leaves and can lead to sooty mould. |
| Habitat |
| Naturally they grow in mixed tropical/maritime lowland areas where temperatures are steady. They grow in forests with high humidity and approximately 3000-4000 mm of annual precipitation. |
| Bark/Stem Description |
| Pale brown grey in colour, the bark is smooth in texture and has aromatic qualities. The tree supports many short, upright branches that end with several flower buds arranged in short panicles. |
| Flower/Leaf Bud Description |
| Flower buds emerge glossy and white, then turn pink and red, mimicking the colour of the petals to come. The buds are smooth, and vase shaped, each one around 1.5 cm long, arranged in small panicles at branch tips. They are produced in the summer and again in the winter. When the tree is about 4 years old, the unopened flower buds are harvested and dried. The leaves emerge from the tips of the branches, beginning as thin, red vegetative tissue pointing straight up from in between two other leaves. They emerge in pairs, as clove leaves have opposite arrangements. |
| Leaf Description |
| New foliage emerges pink, while mature leaves are large, glossy green that are approximately 7-15 cm in length and 2-7 cm in width. They are elliptical in shape with pinnate venation, simple and oppositely arranged. Their margin is entire with no hair present, and they house many aromatic oil glands on their undersides. The petiole reaches about 14 cm long. |
| Flower Description |
| Flowers of this tree emerge pale and glossy. They are light green and become bright red when entering the fruiting stage. In commercial settings, the unopened buds are quickly harvested, so they are often not allowed to bloom. When allowed to mature, petals fall off revealing multiple white flower stamens and the blooming time depends on their climate. Flowers themselves are tubular, containing 4 or 5 petals that are less than 3 cm long. Their inflorescence is called a Cyme. The flowers are also edible and can be dried and eaten. Clove trees are monoecious, meaning male and female flowers are on the same plant, they can self-pollinate but also attract pollinators such as bees. |
| Fruit Description |
| Fruit of a clove tree is an edible, oblong berry and fully matures 9 months after flowering. It is often compared to an olive in its shape and size and is generally around 3 cm long. It is deep burgundy and normally contains only one seed. The berries are properly referred to as “Mother of Cloves.” |
| Colour Description |
| The bark is light brown/grey, and the fruit is a deep burgundy berry. The flowers first emerge white and glossy, then become green, and then vibrant red as they near fruiting. Leaves begin light pink before becoming a rich dark green. |
| Texture Description |
| Clove trees are dense and coarsely textured. Under their bushy foliage they have a considerable amount of short upright branches, and the leaves are wide, thick, and leathery. The bark texture does not change much between old and new growth. |
| Notable Specimens |
| Endebess, a town in the Trans-Nzoia County of Kenya, houses the Multiplant International Medicinal Conservation gardens. Here they cultivate medicinal and aromatic plants suitable for growth in tropical countries. They have many Syzygium species including notable Syzygium aromaticum trees. |
| Propagation |
| Most often propagated by fresh seeds that are collected from the fruit of the most healthy, vigorous trees in the plantation. Seeds are extracted by soaking the fruit and peeling off the skin, they have vitality for about 2 weeks, so should be planted immediately. They are planted in beds or polyethylene bags containing soil and aged manure and are planted at a depth of 2-5 cm, 12-15 cm apart. Germination should happen within 1-6 weeks. The seedlings are kept moist, shaded from direct sunlight, and are transplanted when they reach 30 cm in height. They should be hardened off by exposing them to more and more sunlight before moving into the field. Once transplanted, temporary shade is usually provided by intercropping plants such as bananas, coconut, or cassava trees. These crops are then pruned and manipulated to offer more sunlight to the clove’s underneath. Another way of propagation is to take stem cuttings of terminal leafy softwood and keep in high humidity until rooted. Air layering can also be done in the spring. |
| Ethnobotanical Uses (Disclaimer) |
| Clove trees are a rich resource for food, oils, and pharmaceuticals. They are known as one of the earliest species in the trade and are grown commercially for their flower buds, which are dried to become the clove spice we all know. Oil is collected from the leaves, stem, and buds, and has been discovered to have antibacterial, antifungal and antiseptic properties. The distilled essential oil is used for food flavouring and preservatives, perfumes, pharmaceuticals, and cigarette flavouring. Clove oil contains up to 95% eugenol, which is the main ingredient responsible for its helpful properties. Eugenol has been found to have anticancer, antioxidant, antiseptic, anti-inflammatory, antibacterial, antiviral, antifungal, and antidepressant properties. Clove oil is used to treat conditions such as asthma, arthritis, and skin irritations and is common in dentistry. In the tropics, cloves have been found to affect harmful microorganisms causing malaria, tuberculosis, cholera, and scabies. |
References
Kuete, V., & Mbaveng, A. (2017). Chapter 29 - syzygium aromaticum. In Medicinal spices and
vegetables from africa- therapeutic potential against metabolic, inflammatory,
infectious and systemic diseases (pp. 611-625). Academic press.
https://www.sciencedirect.com/science/article/pii/B9780128092866000297
Linford, J. (2007). A pocket guide to trees. Parragon Publishing.
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