Description

Thai Basil Siam Queen (Ocimum basilicum var. thyrsiflora) is a distinctive Asian basil variety known for its bold anise-licorice aroma, spicy-sweet flavour, and deep purple stems. Its pointed green leaves and lavender-pink flower spikes add both culinary and ornamental appeal. Unlike sweet basil, Siam Queen retains its intense flavour even when cooked, making it a favourite in Thai, Vietnamese, and fusion cuisine.

This variety thrives in South Africa’s warm climates, especially in full sun with well-drained, compost-enriched soil. It grows as a bushy annual, reaching 40-50 cm in height, and is excellent for garden beds, containers, or herb spirals. Quick to mature and resistant to bolting, Basil Thai Siam Queen provides continuous harvests throughout the summer growing season.

As well as adding delicious flavours to your food, Basil Thai Siam Queen can also be greatly beneficial to your plants and soil, even more reason to add it to your garden!

 

Benefits

Companion Planting

• Improves flavour (terpene profile) of other crops such as tomatoes and peppers.
• Planting basil as a companion plant with other produce helps you get bug-free vegetables and fruits as it repels insects such as aphids, beetles, tomato hornworms, mosquitoes and white flies.
  

Insect Repellant & Pollinator

• Repels aphids, whiteflies, and beetles due to its strong aroma.
• Attracts bees and beneficial pollinators, especially when in bloom.
  
• Ideal for inclusion in pollinator-friendly gardens and integrated pest management systems.

Easy to Grow & Versatile

• Grows well in containers or garden beds.
• Heat-tolerant and high-yielding if regularly pruned.
• Adds both culinary and ornamental value to gardens and patios.

Culinary & Medicinal Uses

• Essential in Thai cuisine, perfect for stir-fries, curries, and pho.
• Infused in oils, teas, or used fresh for a flavourful, antioxidant-rich boost.
  
• Traditionally used for digestive support, to ease nausea, and relieve stress.

Nutritional Benefits

• Rich in vitamin A, vitamin K, and vitamin C – supports immunity, eye health, and blood clotting.
  
• Contains eugenol – an anti-inflammatory compound beneficial for joints and reducing swelling.
• Natural source of iron, calcium, and antioxidants.

 

How To Use

Basil Thai Siam Queen flourishes under the following conditions:

• Season: Spring/Summer
• Temperature: 20-30°C
• Germinate: 7-14 days
• Depth: 3 mm
• Spacing: 20x20 cm
• Harvest: 60-90 days
• Height: 40-50 cm
• Flowering Season: Mid to late summer (pinch to delay flowering)
• Exposure: Full sun (6+ hours daily)

Ideal Growing Environment 

• Light, well-drained loam or sandy soil, rich in compost; pH 6.0–7.0.
• Regular but not excessive – keep soil moist but not soggy.
• Organic compost or liquid fertiliser every 3–4 weeks during active growth.
• Basil Thai Siam Queen is sensitive to the cold and prefers warm conditions.
• Prefers moderate humidity (50–70%); ensure good air circulation to prevent fungal issues.
• Basil Thai Siam Queen will grow faster if it is regularly harvested.
• Mulch Basil Thai Siam Queen plants to retain moisture.
• Performs well in most South African summer regions. Not frost tolerant – plant after the last frost in cooler zones.
  
• Benefits from being planted alongside tomatoes, peppers, lettuce, marigolds and oregano.
• Intercropping: Pair with tomatoes, capsicums, broccoli, or strawberries to deter pests.
• Crop Rotation: Use as companions or rotate after heavy feeders. Perennials (rosemary, thyme, lavender) stay in place longer.
• Soil Rejuvenation: Enhance soil microbes; use as borders between cycles.
• Avoid planting with rue, sage, and cucumbers – may stunt growth or compete for resources.

 

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