Evergreen tree 3m-10m, when ripe the fruit turns slightly yellow. Suitable for most soil types but prefers moist well drained soil in full sun. In you live in a location that gets frost plants will need protection. Fertilise before flowering and keep moisture up while fruit is forming.
Psidium species are used as food plants by the caterpillars of some Lepidoptera, mainly moths like the Ello Sphinx (Erinnyis ello), Eupseudosoma aberrans, E. involutum, and Hypercompe icasia. Mites like Pronematus pruni and Tydeus munsteri are known to parasitize the Apple Guava (P. guajava) and perhaps other species. The bacterium Erwinia psidii causes rot diseases of the Apple Guava.
The fruit is not only relished by humans, but by many mammals and birds as well. The spread of introduced guavas owes much to this fact, since animals eat the fruit and disperse the seeds in their droppings.
In several tropical regions, including Hawaii, some species (namely Strawberry Guava, P. littorale, and to a lesser extent Apple Guava) have become invasive species. On the other hand, several species have become very rare due to habitat destruction and at least one (Jamaican Guava, P. dumetorum), is already extinct.
Guava wood is used for meat smoking in Hawaii and is used at barbecue competitions across the United States. In Cuba and Mexico the leaves are used in barbecues.
In Mexico, the guava agua fresca beverage is popular. The entire fruit is a key ingredient in punch, and the juice is often used in culinary sauces (hot or cold), as well as artisan candies, dried snacks, fruit bars, desserts, or dipped in Chamoy. Pulque de Guava is a popular blend of the native alcoholic beverage.
In many countries, guava is eaten raw, typically cut into quarters or eaten like an apple, or with a pinch of salt and pepper, cayenne powder or masala in some countries. It is known as the winter national fruit of Pakistan. In the Philippines, ripe guava is used in cooking sinigang. Guava is a popular snack in Taiwan, sold on many street corners and night markets during hot weather, accompanied by packets of dried plum powder mixed with sugar and salt for dipping. In east Asia, guava is commonly eaten with sweet and sour dried plum powder mixtures. Guava juice is popular in many countries. The fruit is also often prepared in fruit salads.
Because of its high level of pectin, guavas are extensively used to make candies, preserves, jellies, jams, and marmalades (such as Brazilian goiabada and Colombian and Venezuelan bocadillo), and also for juices and aguas frescas or may be used in a marmalade jam on toast.
Red guavas can be used as the base of salted products such as sauces, substituting for tomatoes, especially to minimize acidity. A drink may be made from an infusion of guava fruits and leaves which in Brazil is called ch-de-goiabeira, i.e. “tea” of guava tree leaves, considered medicinal.
Since the 1950s, guavas particularly the leaves have been the subject for diverse research on their constituents, pharmacological properties and history in folk medicine. Most research, however, has been conducted on apple guava (P. guajava), with other species remaining unstudied. From preliminary medical research in laboratory models, extracts from apple guava leaves or bark are implicated in therapeutic mechanisms against cancer, bacterial infections, inflammation and pain. Essential oils from guava leaves display anti-cancer activity in vitro.
Guava leaves are used in folk medicine as a remedy for diarrhea and, as well as the bark, for their supposed antimicrobial properties and as an astringent. Guava leaves or bark are used in traditional treatments against diabetes. In Trinidad, a tea made from young leaves is used for diarrhea, dysentery and fever.