Ocimum is a plant genus that contains about 150 species of herbs and shrubs. It is part of the Lamiaceae plant family, and the plants are commonly referred to as basil. A majority of the species are native to the tropical regions of Asia and Africa. Almost all of the plants in this genus are aromatic and some are used for cooking, including Ocimum basilicum. This species is commonly grown in vegetable gardens.
The common term for this genus, basil, is derived from the Greek word basileus, which translates to "king." Different species in the Ocimum genus have variations on the common name. For example, Ocimum minimum is commonly called bush basil, and Ocimum basilicum is known as sweet basil.
This genus is found throughout the world. Some species are grown in Hawaii, including O. gratissimum, and other species are found in India, such as O. tenuiflorum. O. americanum is present in many countries including Ethiopia, Cameroon, and China.
Most of the species are grown in a garden, container, or border. The foliage of the plant spreads 20 inches (50 cm) in height and width. The majority of the plants in this genus have pointed green leaves that are aromatic. O. minimum has a scent which resembles cloves, and one variety of O. basilicum smells like cinnamon. These plants also produces small, white or pink flowers during the summer.
In order for these plants to grow well, it is recommended to plant them in well-draining, fertile soil. They generally prefer loamy or sandy soil. In terms of pH, Ocimum plants can tolerate both acidic and alkaline conditions. The area in which the plant is placed should be exposed to direct sunlight throughout the day. Also, a location that is sheltered from the wind is ideal.
Most basil plants are vulnerable to insect damage, especially from aphids and leafhoppers. Aphids are small, rounded insects that feed on the leaves of the plant. They also leave behind a sticky residue which attracts fungal spores. Leafhoppers are light yellow and generally hop around the plant. They feed on leaves and usually cause yellow spots.
Another problem associated with basil is powdery mildew, which is a fungal disease. It appears as a dusty white or gray coating on the leaves and shoots. The disease stunts the growth of new shoots and distorts the leaves. Typically, the fungal spores will overwinter in fallen leaves and plant debris, leading to new infections the following season.