Nasturtium
Tropaeolum majus
Also known as: Nasturtium, Garden Nasturtium, Indian Cress, Monk's Cress
'Tropaeolum' derives from the Greek 'tropaion' (trophy), as the round leaves were thought to resemble shields and the flowers like helmets – a botanical trophy monument. The common name 'nasturtium' is shared with watercress (Nasturtium officinale), from the Latin 'nasus tortus' (twisted nose), a reference to the peppery, nose-tingling flavour both plants share. Nasturtium is a vigorous, sprawling annual or short-lived perennial native to South America, now naturalised throughout coastal Australia in gardens, roadsides, disturbed ground, and cliff margins. It is one of the most completely edible plants in this guide – flowers, leaves, stems, and seed pods are all eaten, making it an extraordinarily generous wild food. The bold orange, red, and yellow flowers are unmistakable. It thrives in poor soils, needs little water, and self-seeds prolifically.
When to Forage
Year-round in mild coastal climates; most prolific flowering in spring and autumn. May die back in high summer heat.
Cautions
Very safe and well-tolerated. Mildly diuretic in very large quantities. Avoid harvesting from roadsides with heavy traffic or from sites with known herbicide use. Those with kidney disease should limit consumption of very large amounts (glucosinolates). Some individuals experience mild digestive upset if eating large quantities of raw leaves – the peppery compounds can be strong.
Nutrition
Flowers and leaves: rich in vitamin C, vitamin A (beta-carotene), iron, lutein, and zeaxanthin (for eye health). Flowers contain significant antioxidant flavonoids. Leaves contain glucosinolates (the same antimicrobial, anti-inflammatory compounds found in broccoli and cabbage). Seeds: contain up to 20% protein and useful fatty acids. One of the most nutritionally complete edible-flower plants.
How to Identify
- Distinctive round (peltate) leaves – the stalk attaches to the centre of the leaf rather than the margin, giving a lily-pad appearance. Bright, fresh green, often slightly waxy.
- Flowers are large (3–5 cm), five-petalled, and vividly coloured: orange, yellow, red, or cream, often with dark nectar guides in the throat. A long, curved nectar spur projects backward.
- Sprawling, somewhat succulent stems, scrambling over the ground or climbing through other vegetation. Stems are hollow.
- Seed pods form after flowering: three-lobed, green, and wrinkled, ripening to a tan-brown. Each lobe contains one large seed – the 'nasturtium caper.'
- All parts have a pungent, peppery-mustard smell when crushed.
Lookalikes
Also has round, peltate-looking leaves. Distinguished by much smaller size, less distinctly round shape, and growing in wet, boggy ground rather than open sunny spots. No peppery smell. No showy flowers.
How to Forage
Pick flowers, young leaves, and stems freely by hand. Flowers are best harvested fresh for same-day use – they wilt quickly. Young leaves are the most tender; mature leaves become increasingly peppery and slightly fibrous. Harvest green seed pods before they harden for use as nasturtium capers (pickle in brine and vinegar). The plant is so vigorous that generous harvesting is both possible and environmentally beneficial where it has naturalised and may be crowding out native species.
Recipe — Nasturtium Pesto with Lemon & Walnuts
Ingredients: 2 large handfuls nasturtium leaves (young, tender ones preferred); a generous handful nasturtium flowers (extra for garnish); 1/2 cup toasted walnuts; 2 cloves garlic; zest and juice of 1 lemon; 1/2 cup extra-virgin olive oil; 2 tbsp nutritional yeast or parmesan; salt and pepper. Method: Rinse nasturtium leaves and flowers; spin dry. Combine leaves, walnuts, garlic, lemon zest, and nutritional yeast in a food processor. Pulse until roughly chopped. With the motor running, drizzle in olive oil until emulsified. Add lemon juice, salt, and pepper. Adjust to taste. Serve tossed through pasta, spread on toast, or as a dip. Garnish with whole flowers. Store in a sealed jar with a thin layer of olive oil on top – keeps refrigerated for up to 5 days. Inspo: nasturtium capers – brine green seed pods in salt water for 2 days, then pickle in white wine vinegar with peppercorns. Use anywhere you'd use capers.
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