Native to tropical America, the Guava is a popular fruit tree grown throughout tropical and subtropical parts of the world. With seeds readily carried by birds and bats that also enjoy the fruit, it has become a major environmental weed in parts of South Africa, Australia and Pacific Islands including Hawaii and the Galápagos Islands.
Taxonomy and Description
A member of the family Myrtaceae, the Guava is also known as the Common Guava or Yellow Guava. The Royal Botanic Gardens, Sydney’s Plantnet website describes the Guava as a shrub or tree growing up to 6 m high. Leaves are opposite on the stem, elliptic to oblong with a tapered point. Flowers are white and the fruit is a round to pear-shaped yellow berry with persistent calyx lobes. Inside, numerous hard-coated seeds are embedded in succulent pink flesh. There are numerous cultivars, with fruit size and colour variable.
Growing and Using the Guava
The Guava is a hardy plant growing in a wide range of conditions, preferring warm moist climates but tolerant of dry soils and light frost. It is an important commercial crop in many countries, and is used for nutritious juices, jams, eaten fresh or lightly stewed. Medicinal uses have been attributed to the leaves (antimicrobial properties and for the treatment of diarrhoea).
Ecological Impacts
The Guava can overrun open ground forming monocultural stands, competing for resources with native plants that might otherwise colonise cleared areas. On the Galápagos Islands, hillslopes of moss and lichen-encrusted Guava trees with dense understorey of introduced Rubus species effectively block any regeneration of native species.
Controlling Guava Infestations
Guava trees are difficult to kill. Cut stumps regrow to form multi-stemmed trees. Treatment with low-toxicity herbicides is often unsuccessful as new sprouts from the base of apparently dead trunks and stumps can appear several years after treatment. Expert advice is essential.
Avoiding Weed Problems
Authorities in some districts where environmental weeds are problematic will list and recommend avoidance of some garden species. It may be illegal to grow them. Check locally, and if the Guava is, or potentially could be, an environmental weed in your area, consider responsible options. The Guava can be a disappointing garden or orchard plant. In Australia, untreated fruits succumb to fruit-fly infestation, and birds enthusiastically steal the fruit. It may be preferable to plant an alternative fruit species that does not have invasive potential. If only a Guava will do, net the fruiting trees to avoid removal and seed dispersal by birds and frequently remove and destroy fallen fruit.
Barbara Stewart - I am an Australian ecologist based near Byron Bay on the east coast of the continent. My interests revolve around trees, forests and ...
