Nasturtiums: The Secret Super Plant Every South African Garden Needs
🌼 How to Grow Nasturtiums in South Africa: The Complete Grow Guide for Abundant Flowers, Edible Leaves & Natural Pest Control
Nasturtiums are one of the most rewarding and versatile flowers you can grow in a South African garden. Whether you're planting them in vegetable beds, flower borders, containers, or hanging baskets, these cheerful plants offer far more than just beauty.
They are easy to grow, edible, beneficial for pollinators, and excellent at protecting your vegetable garden from pests.
Better still, they thrive in many South African climates and can be planted both in spring and autumn, making them a favourite among beginner and experienced gardeners alike.
In this comprehensive guide, we’ll explore when to plant nasturtiums in South Africa, how to grow them successfully in each province, how to care for them, and how to save seeds for future planting.
🌿 Why Nasturtiums Are a Must-Have Plant in Every South African Garden
Nasturtiums (Tropaeolum majus) are incredibly useful plants that serve many purposes in the garden.
Here’s why gardeners love them:
🌸 Beautiful bright flowers in shades of orange, yellow, red, cream and bi-colours
🥗 Edible leaves and flowers with a peppery flavour similar to rocket
🐝 Attract pollinators like bees and beneficial insects
🐞 Natural pest control – acts as a trap crop for aphids
🌱 Excellent companion plant for vegetables
🪴 Perfect for pots, borders, and hanging baskets
🌿 Extremely easy to grow from seed
Because they grow quickly and require little maintenance, nasturtiums are often recommended as one of the best flowers for beginner gardeners.
📅 Best Time to Plant Nasturtiums in South Africa
Unlike many annual flowers that prefer spring planting only, nasturtiums grow beautifully when planted in two different seasons.
🌱 Spring Planting
August – October
Spring planting produces strong plants that flower through spring and summer.
🍂 Autumn Planting
March – May
Autumn planting is often even better in South Africa because:
✔ Cooler temperatures improve germination
✔ Plants establish before winter
✔ Flowering often continues through winter in mild areas
✔ Less pest pressure than mid-summer
In many parts of South Africa, autumn-sown nasturtiums provide colour throughout winter and early spring.
🇿🇦 Growing Nasturtiums in Different South African Provinces
South Africa’s climates vary widely, so planting times and care may differ slightly by region.
Gauteng & Highveld (Johannesburg, Pretoria)
Climate: Warm summers, cool dry winters with frost.
Best planting times
🌱 March – April
🌱 August – September
Growing tips
• Plant in full sun for best flowering
• Protect young plants from heavy frost
• Ideal for vegetable gardens and raised beds
Autumn planting works well here because plants establish before winter and often survive light frost.
Western Cape
Climate: Mediterranean with wet winters and dry summers.
Best planting times
🌱 March – May
🌱 August – October
Autumn planting is particularly successful here.
Growing tips
• Sow before winter rains begin
• Ensure well-draining soil
• Great for cottage gardens and containers
In the Western Cape, nasturtiums can grow right through winter and flower beautifully in spring.
KwaZulu-Natal
Climate: Warm and humid with mild winters.
Best planting times
🌱 March – May
🌱 August – October
Nasturtiums grow well almost year-round here but prefer cooler periods.
Growing tips
• Choose a spot with morning sun
• Avoid overly rich soil
• Provide airflow to reduce humidity issues
Eastern Cape
Climate varies between coastal and inland regions.
Best planting times
🌱 March – May
🌱 August – October
Coastal gardens can enjoy nasturtiums through much of the year.
Free State & Northern Cape
Climate: Hot summers and cold winters.
Best planting times
🌱 Early autumn (March)
🌱 Early spring (August)
Growing tips
• Plant before extreme heat or frost
• Water consistently during establishment
• Mulch lightly to retain soil moisture
Limpopo & Mpumalanga
Climate: Warm to hot summers, mild winters.
Best planting times
🌱 March – April
🌱 August – September
Avoid planting during peak summer heat.
🌱 How to Plant Nasturtium Seeds
Nasturtiums are very easy to grow from seed, and they actually prefer to be planted directly into the soil.
Step-by-step planting
1️⃣ Choose a sunny location
2️⃣ Sow seeds 2–3 cm deep
3️⃣ Space plants 20–30 cm apart
4️⃣ Water lightly after planting
5️⃣ Seeds usually germinate within 7–14 days
They can also be grown in pots, containers, raised beds or hanging baskets.
☀️ Soil & Sun Requirements
Nasturtiums prefer simple growing conditions.
🌞 Sunlight
Full sun produces the most flowers.
🌱 Soil
Surprisingly, they prefer poor to average soil.
Too much fertiliser encourages leaves instead of flowers.
💧 Watering Nasturtiums
Water lightly during germination and early growth.
Once established they are relatively drought tolerant, making them suitable for water-wise gardens.
Avoid overwatering as this can reduce flowering.
✂️ Should Nasturtiums Be Pruned or Deadheaded?
Yes — light pruning helps keep plants flowering longer.
Deadheading
Removing old flowers encourages the plant to produce more blooms.
Trimming
If plants become leggy or untidy:
✂️ Trim them lightly
✂️ This stimulates fresh growth and new flowers.
Trailing varieties can grow quite vigorously and may benefit from occasional shaping.
🌼 Should You Fertilise Nasturtiums?
In most cases no fertiliser is needed.
Too much fertiliser leads to:
❌ Excess leafy growth
❌ Fewer flowers
If your soil is extremely poor, you can add a light compost dressing when planting.
🐞 Nasturtiums as Natural Pest Control
Nasturtiums are famous for their role as a trap crop.
They attract pests away from your vegetables.
Common pests they attract include:
🐛 Aphids
🐞 Whiteflies
🐌 Some caterpillars
Because pests prefer nasturtiums, they often leave your vegetables alone.
This makes them ideal companions for:
🥬 Lettuce
🥦 Cabbage
🍅 Tomatoes
🌶 Peppers
🥒 Cucumbers
🌿 Herbs
Many gardeners plant nasturtiums around the edges of vegetable beds as a natural defence system.
🐝 Pollinators Love Nasturtiums
Their bright flowers attract beneficial insects like:
🐝 Bees
🦋 Butterflies
🐞 Ladybirds
These insects improve pollination and help control pests naturally.
🥗 Are Nasturtiums Edible?
Yes! Both the leaves and flowers are edible.
They have a peppery flavour similar to rocket.
Uses include:
🥗 Salad garnish
🌼 Edible flower decoration
🥪 Sandwiches
🧂 Herb-style flavouring
Even the seeds can be pickled and used as a capers substitute.
🌱 Saving Nasturtium Seeds
One of the best things about nasturtiums is how easy they are to save seed from.
After flowering, the plants produce large round seeds that drop to the ground.
How to collect seeds
1️⃣ Allow seeds to dry on the plant
2️⃣ Collect them once they fall or turn beige
3️⃣ Let them dry further indoors for a few days
📦 How to Store Nasturtium Seeds
Store seeds in:
📄 Paper envelopes
📦 Glass jars
🪵 Wooden boxes
Keep them in a cool, dry, dark place.
Properly stored seeds can remain viable for 2–3 years.
🌼 When to Replant Saved Seeds
Saved seeds can be planted again during:
🌱 Spring (August–October)
🍂 Autumn (March–May)
Many gardeners simply allow nasturtiums to self-seed naturally, and they return every year.
🌿 Nasturtiums in Vegetable Gardens
These plants are particularly valuable in companion planting systems.
Benefits include:
✔ Improved biodiversity
✔ Natural pest management
✔ Pollinator attraction
✔ Beautiful colour among vegetables
They are commonly planted alongside:
🥬 Brassicas
🍅 Tomatoes
🌿 Herbs
🌶 Chillies
🌸 Nasturtiums truly are one of the most useful plants you can grow in a South African garden.
They combine beauty, practicality and ease of care, making them perfect for:
🌱 Beginner gardeners
🌿 Vegetable gardens
🪴 Containers and patios
🌼 Pollinator-friendly gardens
With the ability to plant them in both spring and autumn, they provide colour and benefits across much of the year.
If you're looking for a low-maintenance flower that supports your entire garden ecosystem, nasturtiums are hard to beat.
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