The 20 Flavour Expressions of Nasturtiums

Most people think nasturtiums taste “peppery” and stop there. In reality, nasturtiums have one of the widest flavour ranges of any edible garden plant. The taste can shift from mild and sweet to sharp, spicy, citrusy, or even caper-like depending on the variety, how it is grown, and when it is harvested.

What makes this possible comes down to plant chemistry.

Nasturtiums contain natural compounds called glucosinolates. These are the same family of compounds found in mustard greens, arugula, and horseradish. When you bite into a leaf or flower, those compounds turn into mustard oils. That reaction is what creates the heat and spice people recognize. Scientists call the main one benzyl isothiocyanate, but all you need to know is this: the plant makes its flavour fresh, right when you eat it.

Everything else you taste sits on top of that base heat.

Core Nasturtium Flavour Families

These flavours are driven mainly by mustard-oil compounds that activate when the plant is chewed, cut, or crushed, combined with sugars and aromatics in the leaves, flowers, or seeds.

Peppery mustard

This is the classic nasturtium flavour. It comes from mustard oils that activate immediately when the plant tissue is broken. The heat is bright and forward, similar to mustard greens. Most noticeable in young leaves and sun-grown plants.

Cultivars: Empress of India, Jewel Mix, Tall Single Mix, Alaska Mix

Mild Pepper

A softer version of the same mustard chemistry, usually because the plant is young, well watered, or grown in partial shade.

Often preferred for fresh salads.

Cultivars: Peach Melba, Milkmaid, Whirlybird Cream

Arugula-like

This flavour sits between leafy greens and spice. The heat is present but balanced by a green, slightly bitter undertone.

Best harvested from young to mid-aged leaves.

Cultivars: Alaska Variegated, Cherry Rose

Watercress-like

Clean, crisp heat without lingering bitterness. This happens when the mustard oils are strong but the leaf chemistry stays fresh.

Morning harvest makes a noticeable difference.

Cultivars: Jewel Mix, Lemon Gem

Radish-like

Dry, sharp bite that fades quickly. This comes from strong mustard oils with very little sweetness to soften them.

Often strongest in full sun.

Cultivars: Scarlet Gleam, Red Chief

Horseradish-like

This is a nasal heat that clears the sinuses. It happens when mustard oils dominate completely and aromatics are intense.

Usually strongest in stressed, sun-grown leaves used fresh.

Cultivars: Wild-type Tropaeolum majus, Tall Orange

Wasabi-like

Very sharp, fast heat that rises and disappears quickly. This is similar to horseradish but more fleeting.

Often noticed in freshly torn leaves.

Cultivars: Empress of India, heritage seed strains

Bitter Green

Bitterness comes from older leaves and plant stress rather than sweetness or nectar.

Some cooks like this for balance, others avoid it.

Cultivars: Black Velvet, Mahogany

Sweet Floral

Low heat with a soft floral sweetness. Mostly found in flowers rather than leaves.

Harvest fresh blooms early in the day.

Cultivars: Cream Troika, Moonlight

Honeyed Floral

Stronger sweetness from nectar, often in pale or cream flowers.

Very time sensitive and best used immediately.

Cultivars: Butterscotch, Milkmaid

Cucumber Fresh

Cool, refreshing, and mild with very little heat.

Usually from very young leaves grown with consistent moisture.

Cultivars: Whirlybird Yellow, Alaska Gold

Green Bean Fresh

Soft vegetal flavour with minimal spice.

Appears in early growth stages before mustard oils intensify.

Cultivars: Whirlybird Cream, Peach Melba

Spicy Citrus

Pepper heat balanced with lemon or zest-like brightness.

Lean soil and sun encourage this expression.

Cultivars: Lemon Gem, Moonlight

Clean Vegetal

Very mild, green, and neutral. Often grown more for appearance than flavour.

Young leaves only.

Cultivars: Alaska Variegated, Variegatus

Secondary and Situational Flavour Expressions

These flavours appear depending on age, stress, plant part, and harvest timing. They are real, but less predictable.

Metallic Sharp

A sharp edge that can feel mineral-like. Often from older leaves or drought stress.

Cultivars: Tall Single Mix, older Empress of India plants

Sulfurous Bite

A deeper mustard-oil presence that reads as heavy or pungent.

Often strongest when leaves are crushed rather than sliced.

Cultivars: Heritage Tropaeolum majus strains

Herbal Grassy

Fresh cut herb flavour layered over mild spice.

Appears in fast-growing plants harvested early.

Cultivars: Cherry Rose, Peach Melba

Resinous Pepper

Pepper heat with a slightly sticky or aromatic finish.

Often linked to dark-leaved varieties.

Cultivars: Black Velvet, Mahogany

Warm Mustard Oil Finish

Heat that builds slowly and lingers after swallowing.

Usually from mature leaves and seed pods.

Cultivars: Tall Orange, Tall Single Mix

The Seed Pod Flavour Everyone Misses

Caper-like heat from seed pods

Unripe green nasturtium seeds are intensely spicy and are often pickled as a caper substitute. Harvest them while still green and firm. Any seed-grown nasturtium can do this. This flavour has nothing to do with the flowers.

Cultivars: Any Tropaeolum majus allowed to seed

Seed or Cuttings: What You Should Use

Most nasturtiums grow perfectly well from seed. Seed-grown plants give variety, which is great for home gardeners. If you want reliable flavour that tastes the same every time, cuttings are the answer.

Cuttings keep the exact same chemistry as the parent plant. This matters if you are growing nasturtiums for specific dishes, selling edible flowers, or cooking professionally. Cuttings root easily in water or moist soil and grow faster than seed.

Some unusual or specialty nasturtiums do not produce reliable seed. These must be kept through cuttings, even though most garden varieties do not require this.

The One Rule That Changes Everything

Nasturtium flavour depends more on when you harvest than what variety you plant.

Young leaves are brighter and cleaner.

Older leaves are stronger and sometimes bitter.

Flowers are milder than leaves.

Morning harvest tastes better than afternoon harvest.

Rich soil makes big plants with less flavour.

Once gardeners understand this, nasturtiums stop being unpredictable and start becoming intentional flavour plants.