Herb of the Year 2003: Basil (Ocimum basilicum)

Basil: Herb of the Year 2003

Basil: Herb of the Year 2003

The International Herb Society has designated basil as the Herb of the Year 2003. Sweet basil (Ocimum basilicum) is a sun-loving annual with highly aromatic leaves that has a pleasant spicy odor and taste somewhat like anise or cloves. Both the leaves and their essential oils are used as flavoring agents. There are many different types of sweet basil – large and dwarf forms, with green, purple, or variegated leaves. Many of these widely grown plants are ornamental, as well as edible.

The genus Ocimum is native to Asia, Africa and Central and Southern America. Basil was probably first cultivated in India, and was introduced in ancient times to Africa and the Mediterranean through the spice routes. Basils belong to the mint family, and have the square stems, opposite leaves, flower spikes, and oil glands typical of many members of this plant family. The ancient Greeks called basil “The Herb of Kings.” (The name for sweet basil comes from the Greek okimon, basil, and basilikos, royal.) It was believed that only the king himself should harvest this herb, and only using a golden sickle. In Romania, basil had a different meaning: when a man accepted a sprig of basil from a woman, he was officially engaged. The meaning in Greece was less romantic – there it was a symbol of death and hatred!

Like many herbs, basil has many reputed medicinal properties, such as the ability to draw out poison from insect bites, as a sedative, for treating digestive disorders, soothing pain, promoting perspiration, and promoting production of breast milk in nursing mothers.

Varieties

There are many cultivars of sweet basil available today, as well as several related species of Ocimum that are also used for cooking and ornamental purposes. Most vegetable seed retailers offer a number of choices.

  • Cinnamon basil.

    Cinnamon basil.

    Cinnamon basil has distinctive cinnamon-colored stems, purple flowers tinged with bronze, and small- to medium-sized, dark green leaves. These ornamental plants can reach 3 feet in height and width, and the leaves have a cinnamon-like taste and odor.

  • ‘Dark Opal’ has beautiful deep red-purple foliage and lovely pink flowers. In addition to culinary use, it makes a nice, fragrant border along a walkway.
  • ‘Genovese’ (or ‘Genova’) is a standard, flat-leafed Italian type commonly used for making pesto. The leaves are 3-4 inches long and 2-3 inches wide, with a sweet, spicy taste. Plants can reach 5 feet, but are more productive if kept pruned back.
  • Holy basil (O. tenuiflorum or sanctum; also called Tulsi or Sacred Basil) has highly aromatic, narrow oval leaves and pink flowers with a perfumed fragrance. It grows to about 18 inches high. Both red and green leafed varieties occur.
  • Lemon basil (O. americanum or citriodorum) has small, light green leaves and a lemony fragrance. It is often used in Indonesian cuisine or to flavor fish, and can be added to tea for an interesting lemony flavor.
  • ‘Magical Michael’, a 2002 AAS winner, reliably grows uniformly 15 inches tall and 16-17 inches wide (uniformity is rare in sweet basil plants). The small purple and white flowers are attractive as a garnish, and as an ornamental are very attractive to bees.
  • ‘Nufar’ is a Fusarium wilt-resistant Genovese-type plant with mild flavor.
  • ‘Purple Ruffles’ has very large, dark shiny purple-black, ruffled and fringed leaves and pink flowers. It is ideal for providing contrast in bedding or containers, as well as being an edible herb. Other purple basils include ‘Purpurascens,’ ‘Opal’, and the dwarf ‘Minimum Purpurascens.’
  • Purple basil.

    Purple basil.

    ‘Red Rubin’ is a new purple leaf variety that maintains its deep color through the season.

  • ‘Siam Queen’ is a very fragrant selection with extra large, bright green leaves on large, purple-red stemmed plants that bear violet-pink flowers. It works well as a container plant or edging beds, as well as in the vegetable garden. Especially good for Thai cuisine.
  • ‘Spicy Globe’ forms a compact plant about 6 inches high and 12 inches across. Can be used in the border or as a container plant.
  • ‘Sweet Dani’ is a narrow leaved, lemony variety developed at Purdue University that was a AAS winner in 1998.

Cultivation

Basil is easily grown from seed.

Basil is easily grown from seed.

Basil is easily grown from seed, or can be purchased as small potted plants. Plant seeds early in spring, sowing the seed at a half an inch deep. They can be sown directly in the ground after all danger of frost has passed, or can be started indoors 4-6 weeks before setting out (use 2-3 seeds per pot) for earlier harvests. Germination can occur in 5 to 7 days, but will take longer under cool conditions. Place plants outside12-15 inches apart.

Basil is a warm season plant, requiring temperatures above 50º to grow, but does best when temperatures are in the 80s and 90s. Plant basil in full sun, in well-drained soil. Water adequately to produce tender leaves, but be careful not to overwater. Basil needs more fertilizer than most herbs. Incorporate compost before planting or top dress at planting to keep the plants producing leaves all season.

Basil produces spikes of white or pink flowers.

Basil produces spikes of white or pink flowers.

Pinch off the terminal shoots to encourage branching and tender new growth, and slow down flower production. When the plant stems become woody and stop producing, cut the plants back a third and fertilize to stimulate new growth. In midseason the plants will begin to produce spikes of small white, pink or purple flowers. Remove these flower spikes to keep the plant producing leaves up to frost.

Basil is generally easy to grow, but may be attacked by common garden pests such as spider mites (especially when hot and dry), aphids, Japanese beetles, or other insects. These can be controlled by hosing off the plants or applying insecticidal soap, or removing the beetles by hand. A few generalist fungal or bacterial diseases may occasionally affect individual plants. Root rots (or damping off of seedlings) occur primarily when the soil is too wet.

Basil sown in pots in midsummer can be brought indoors to continue growing during the winter. Place the pot in a bright, sunny window for best results.

Harvest

Harvest basil by pinching or cutting terminal shoots.

Harvest basil by pinching or cutting terminal shoots.

Selectively remove individual leaves or pinch off tips that have one or two sets of leaves as needed for fresh use at any time. Basil does not refrigerate well, but can be kept there for a few days. Another alternative is to place the stems in water to keep the sprigs fresh for a few days.

Just before the plants begin to flower, the whole plants can be cut 6-8 inches from the ground. Basil is a very tender plant and will be damaged by frost, with the leaf tissue turning black. Either cover the plants completely or make a final harvest when the first frost is predicted.

Basil can be preserved by drying, but does not freeze well.

Uses

Basil is most commonly associated with Italian and Thai cuisine. Most Italian dishes with tomatoes also use basil. Basil is the essential ingredient in pesto. The leaves, fresh or dried, may be used in many other dishes, as well. Infusions of the leaves can flavor oil or vinegar, and leaves can be steeped for teas.

Recipes that take advantage of this herb are endless; just a few examples are offered here.

Basil Dipping Oil
From Cooking Light Magazine. 2 cups chopped fresh basil leaves (about 2 (3/4-ounce packages)
1/2 cup olive oil
Combine basil and oil in a small, heavy saucepan. Cook over medium-low heat until thermometer registers 180 degrees. Reduce heat to low; cook 20 minutes (do not allow temperature to rise above 200 degrees). Cool to room temperature. Drain oil mixture through a sieve into a bowl; discard solids.
Classic Pesto
From Cooking Light Magazine. 2 tablespoons coarsely chopped walnuts or pine nuts
2 garlic cloves, peeled
3 tablespoons extra-virgin olive oil
4 cups basil leaves (about 4 ounces)
1/2 cup (2 ounces) grated fresh Parmesan cheese
1/4 teaspoon salt

Drop nuts and garlic through food chute with food processor on; process until minced. Add oil; pulse 3 times. Add basil, cheese, and salt; process until finely minced, scraping sides of bowl once.

Spoon into a zip-top, heavy-duty plastic bag or other container; store in refrigerator.

Basil and Tomato Bruchetta
crusty Italian bread, 1 inch thick
olive oil
ripe tomatoes, peeled, seeded and diced
chopped fresh oregano
basil leaves, cut into small pieces
garlic cloves, peeled and minced
salt and pepper
optional: Parmesan or Asiago cheese, grated

Toast bread over a grill or in the oven at 425º. Brown on both sides. Remove and brush with oil.

In a bowl combine tomatoes*, oregano, basil, garlic, salt and pepper. Top warm bread with mixture and sprinkle with cheese, if desired. (The cheese can also be mixed in with the tomatoes).

*I salt the diced tomatoes, and let them drain 15-30 min. in a strainer to remove some of the juice, before adding the other ingredients.

– Susan Mahr, University of Wisconsin – Madison


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Additional Information

  • Basil – a 2-page Herb Society of America Fact Sheet
  • Sweet Basil – by Botanical.com, a Modern Herbal

3 comments

  1. Warm season plant that does well in the 80’s and 90’s temp wise

  2. Basil in called the Herb of Kings and medicinal properties. It can be grown from seed but does not freeze well.

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