Is Basil a Perennial or an Annual?
Basil (Ocimum spp.) is a widely used herb that can be grown in the home garden. Native to Southeast Asia, India and Africa, it is easy to grow and is usually cultivated as an annual plant. It is primarily grown for its leaves, but the flowers of basil are edible too.
Can You Grow Basil as a Perennial?
In its native habitat, basil is a perennial that can survive for more than one growing season. However, these plants are only hardy in U.S. Department of Agriculture plant hardiness zones 10 to 12. Therefore, in most places, basil is treated as an annual. This means that you should plan on replanting it each spring.
Types of Basil
Let's take a look at some of the different kinds of basil.
By far the most widely grown and used type of basil is sweet basil (Ocimum basilicum), which is known as common basil. There are many cultivars of sweet basil from which to choose that vary in the size and color of the leaves as well as in flavor.
- Genovese: This cultivar can grow up to 2 feet tall and has large, 2-inch leaves. It is the go-to basil for making pesto.
- Sweet Broadleaf: A smaller plant than Genovese, it has a height of up to 18 inches. The leaves are medium-size.
- Purple Ruffles: This kind of basil is grown for its ornamental purple leaves, which are also edible.
- Cinnamon: This cultivar gets its name from its flavor, which is spicier than that of other sweet basils.
- Thai: This popular cultivar grows up to 18 inches, is slightly spicy and is more stable under high or extended cooking temperatures than other cultivars of sweet basil.
Holy basil (Ocimum tenuiflorum) is a variety of basil used in Asian cuisine that has a spicier taste than sweet basil. This type of basil is more commonly cooked into dishes rather than eaten raw. Holy basil grows in shrub form. Shrubs quickly reach a height of about 3 feet.
African Blue Basil
African blue basil (Ocimum kilimandscharicum x basilicum) is a hybrid version of basil that, according to the University of Florida IFAS Extension, is grown primarily for its flowers, which are attractive to pollinators, like bees and wasps. It is edible but has a much stronger taste than sweet basil.
The pink flowers of the African blue basil do not produce seeds. This variety of basil can therefore only be propagated by cuttings.
Growing Basil in the Garden
You can sow basil seeds directly into the garden bed in spring after the last frost of the season. According to the University of Minnesota Extension, basil plants perform best in soil that has a pH between 6.0 and 7.5 and drains well.
When planting basil, choose a location where the plants will receive between six and eight hours of sunlight a day. Basil plants also need about an inch of water a week.
Basil can be harvested on an ongoing basis, as that plant will continue to produce leaves from the point where the cut was made. For the best quality and flavor, harvest basil leaves when you are ready to cook with them.
If you are not ready to use basil and the growing season is coming to an end, you can harvest the leaves and either dry them in the oven or freeze them.
- North Carolina State Extension: Ocimum basilicum
- North Carolina State Extension: Ocimum tenuiflorum
- North Carolina State Extension: Ocimum kilimandscharicum x basilicum
- University of Florida IFAS Extension: Basil
- Iowa State University Extension and Outreach: Basil
- Missouri Botanical Garden: Ocimum basilicum
- University of Minnesota Extension: Growing Basil in Home Gardens
- University of Florida IFAS Extension: African Blue Basil: A Pollinator Favorite
- Utah State University Yard and Garden Extension: Basil in the Garden
Since beginning her career as a professional journalist in 2007, Nathalie Alonso has covered a myriad of topics, including arts, culture and travel, for newspapers and magazines in New York City. She holds a B.A. in American Studies from Columbia University and lives in Queens with her two cats.