As more interesting and exotic herbs from various cultures enter into the mainstream gardening world, there is often confusion in respect to the names and identities of the plants in question. One such plant is Tulsi, also confusingly referred to as Holy Basil or Sacred Basil. Common names can be a nightmare for horticulturists, as a single common plant name may refer to two or more quite different plants which may be closely related or sometimes completely unrelated.
Tulsi is a common name which refers to many varieties of basil that are of significance in the Indian subcontinent. What distinguishes them from many other basils is the presence of large amounts of the compound eugenol which imparts a clove-like aroma. What differentiates the various varieties of Tulsi from each other is their appearance, cold hardiness and how they are used traditionally.
Many varieties of Tulsi or Holy Basil can be found in the Indian subcontinent, but to simplify matters, it’s easier to consider the three main varieties, which also happen to be the varieties available in Australia.
Holy Basil also known as Sacred Basil, Wild Tulsi, Forest Tulsi or Vana Tulsi (Ocimum gratissimum) is a different species to the other two. It’s a large vigorous plant growing to 3m tall x 2m wide in its native climate. It can be distinguished by its larger broad green leaves, green stems and short flower heads. This plant is used as a ceremonial herb in Indian spiritual traditions.
Tulsi plant, also known as Krishna Tulsi (Ocimum tenuiflorum syn. Ocimum sanctum), is a small delicate plant growing to 60cm in height. It is identifiable by its smaller purple or dark green leaves with purple veins, and dark purple stems. It also has a characteristic taste, which is described as peppery, sharp and crisp. This plant is used as a medicinal herb in Ayurvedic medicine.
Green Leaf Tulsi, also known as Rama Tulsi (Ocimum tenuiflorum syn. Ocimum sanctum), is the same species as Krishna Tulsi, so it has a similar form, but this variety has green leaves, and grows to around 90cm in height. Unlike the other larger-growing green-leafed Vana Tulsi, this plant has smaller, more elongated leaves and produces long flower heads. It has a distinctive taste that is described as slightly sweet, cooling, and mellower than the other Tulsi varieties. Rama Tulsi is the most fragrant of all the Tulsi varieties, the scent is a combination of the characteristic Tulsi clove-like scent, together with that of aniseed, lemon and peppermint. This plant is also used as a medicinal herb in Ayurvedic medicine.
These three varieties of Tulsi are perennial in warmer climates, but are treated as summer annuals if grown in cooler temperate climates outdoors. Vana Tulsi is a more cold tolerant species than Krishna and Rama Tulsi, and may survive in a protected sunny location outdoors planted near a north or west facing wall that retains the heat at night in winter, but all three can be grown in pots and kept in a bright sunny location indoors over winter.