Ocimum ‘African Blue’, commonly known as African Blue Basil, is a rare, aromatic hybrid basil prized for its ornamental beauty and bold, complex flavor. It combines ornamental splendor with rich culinary potential, making it a garden standout. Its striking purple-green foliage, camphor-scented blooms, and pollinator-attracting flowers make it a vibrant, multi-purpose herb.
African Blue Basil does not occur naturally in the wild-it is a manmade hybrid first discovered in Ohio in the early 1980s. As noted in its scientific name, it is a cross between Ocimum kilimandscharicum, a camphor basil native to East Africa, and a cultivar of basilicum, 'Dark Opal', also native to Africa and to Southern Asia. Because it is sterile, African Blue Basil does not produce viable seeds.
This plant is a short-lived perennial in warm climates and is often grown as an annual elsewhere. Heat tolerant, African Blue Basil is perennial in USDA zones 10-11 but is typically grown as an annual in colder regions.
Growing Conditions
Here's what you need to know to provide the best environment for your African Blue Basil:
- Location: Full sun (6-8 hours daily). Some partial shade is tolerated in the afternoons in hot climates.
- Soil: Plant in well-draining, humus-rich soil. It does well when given compost and/or regular fertilizer.
- Water: African Blue Basil prefers for the soil to dry out between waterings and should be watered regularly. Water deeply when the top inch of soil is dry.
- Humidity: African Blue Basil doesn’t require additional humidity.
Once established the plant can tolerate drier soils, but it is by no means a drought-tolerant plant. Plant it in full sun and in moist, well-drained, humus-rich soil. This plant is more heat tolerant than other basils.
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African Blue Basil grows well in indoor settings more than many other herbs. In the landscape, plant it in a container or a culinary herb, sensory, or pollinator garden.
Plant Sizes
Here are some common pot sizes and corresponding plant heights:
- 3 inch Pot - 8 to 12" tall plant in 6" diameter x 7" tall pot
- 1 gallon Pot - 8 to 16" tall plant in 5" x 5" x 6" tall pot
- Small Tree Pot - 8 to 16" tall plant in 5" x 5" x 6" tall pot
- Large Tree Pot - 8 to 16" tall plant in 5" x 5" x 12" tall pot
- 3 gallon Pot - 18 to 36" tall plant in 10" diameter x 8" tall pot
- 5 gallon Pot - 30" to 60" tall plant in 11" diameter x 10" tall pot
- 15 gallon Pot - 60" to 75" tall plant in 17" diameter x 15" tall pot
Here is a table summarizing the information:
| Pot Size | Plant Height | Pot Dimensions |
|---|---|---|
| 3 inch Pot | 8-12" | 6" diameter x 7" tall |
| 1 gallon Pot | 8-16" | 5" x 5" x 6" |
| Small Tree Pot | 8-16" | 5" x 5" x 6" |
| Large Tree Pot | 8-16" | 5" x 5" x 12" |
| 3 gallon Pot | 18-36" | 10" diameter x 8" tall |
| 5 gallon Pot | 30-60" | 11" diameter x 10" tall |
| 15 gallon Pot | 60-75" | 17" diameter x 15" tall |
Fertilizing and Repotting
African Blue Basil is a fast growing plant and may deplete the nutrients in its soil over time. To replenish this plant's nutrients, repot your African Basil after it doubles in size or once a year-whichever comes first. Replenish them with a gentle organic fertilizer or compost every 1-2 months depending on your location and season.
Pruning
As the rapidly growing plant matures, its stems may become woody and heavy, sometimes flopping over. Trim unwanted branches back, and new growth will appear out of old stems. Because it does not produce seed, its flowers do not need to be pinched back to keep the plant growing like other basils. Flowers do not have to be pruned to extend the life of the plant, but they can be pruned for bushier growth and a cleaner look.
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From summer into fall, African Blue Basil produces long, showy spikes of lavender-pink flowers along dark purple stems. Add African Blue Basil Flowers to sour cream for baked potatoes, top your favorite pasta dish with them or float them in ice trays and add to ginger ale, champagne or white wine spritzers.
Common Issues
Yellow leaves aren’t always a reason to panic, and can be a normal part of a plant’s life cycle. Overwatering and root rot are the most likely cause of problems in African Basil, since they are sensitive to wet soil. The leaves may also appear to be curling or drooping.
Yellow leaves can be a sign of overwatering or other issues.
Propagation
African Blue Spice Basil: How To Grow & Propagate
African blue basil plants, however, are sterile (they're hybrids), so true African blue basil seeds do not exist. That means you can only create more African blue basil plants by rooting cuttings. Fortunately, African blue basil is one of the easiest herbs to propagate.
Supplies Needed:
- Organic basil from the grocery store or garden
- A glass of fresh water
- Some pruners or some really sharp scissors
- A shallow cup
- A small container filled with potting mix (needed later)
Steps to Propagate African Blue Basil:
- Select the Basil Stems to Root: Buy a single bunch of organic African blue basil from the grocery store or take some fresh cuttings from healthy plants in the garden. Cuttings should be about four inches long. Select the best stems to turn into plants by sorting through your bunch and finding the healthiest, freshest-looking leaves.
- Prepare the Stems for Propagation: Clear the stems by removing the lower leaves on the bottom inch or so of the cuttings. This will allow the plant to focus on growing roots. Using clean pruners or sharp scissors, cut the stem at a bit of an angle.
- Place Basil Cuttings in Water: Put trimmed and cleaned cuttings in a glass of fresh water. You want to make sure the leaves are hanging out all nice and dry at the top, but that the stem is nicely submerged since that’s where the roots will emerge. Place your glass near a spot with filtered sunlight, somewhere that doesn't get too hot or cold. Keep the cuttings in the water for ten to 14 days, replacing the water every two to three days. Remove molded or yellowing leaves and monitor the cuttings as they root.
- Prepare a Container to Grow Basil: Once you observe the formation of roots, prepare a 6"- to 12"-wide pot with organic potting mix. Water the mix thoroughly before transplanting.
- Grow Basil in a Pot: Dig a hole the depth of the cutting and at least twice the width of the cutting. Place the cutting into the new pot and water in well. Ensure the re-potted cutting stays well-watered by watering every two to three days. Keep in a spot with filtered light without extreme temps. Baby your new plants for the next couple of weeks as they adjust to life in soil instead of water.
In the spring, you can move your basil plants outside to a semi-shaded area once the threat of frost has passed. The best part is, you can keep taking cuttings from your plants and propagating them all over again.
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Culinary and Medicinal Uses
African blue basil plants have long been grown for the medicinal and culinary uses of the leaves. The smooth, broad leaves start deep purple when young and turn green with purple veining as they mature. The foliage is fragrant and flavorful, with an earthy, camphor-like aroma and notes of clove, musk, and menthol.
Culinary: Edible leaves, stems, and flowers. The leaves are sweeter than most green basils which is great for tea, salads, rice or pasta dishes. Basils do not dry well, but leaves and flowers can be pureed with olive oil and frozen for winter use. Use about 3 cups leaves to 1/3 cup olive oil and store flat in small resealable bags.
Medicinal: In its native Africa, the plant is also well-known for several medicinal uses, including as an insect repellant. Some of the other potential medicinal uses include treating fever, parasites, bacterial infections, colds, headaches, and gastrointestinal problems.
