How to grow Nasturtium in Australia
Nasturtium (Tropaeolum majus) is an easy, cheerful annual with round leaves and bright orange, red and yellow flowers. Every part above ground is edible, with a peppery taste, and it earns its place in the vegie patch by drawing aphids and cabbage white butterflies away from other crops.
📖 Our full guide: How to Grow Nasturtium in Australia
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| South East Queensland | March to October | |
| Northern Rivers NSW | March to October | |
| Sydney & Coastal NSW | March to May, September to November | Sow in autumn on the frost free coast for winter and spring flowers, or in spring everywhere. Frost cuts it down in the west and midsummer heat stalls it. |
| Melbourne & Victoria | September to December | Sow Sep to Dec once frost risk fades. Self-sows year-round in frost-free bayside pockets. |
| Adelaide & SA | March to May, September and October | On the plains autumn sowings grow through the mild winter and flower in spring. In the frosty Hills sow Sep to Oct. Dies back in summer heat. |
| Perth & WA | March to October | |
| Tasmania | October to December | Sow Oct to Dec. Self-seeds in mild coastal gardens. Frost ends it in autumn. |
| Canberra & ACT | November and December | Frost tender. Direct sow Nov to Dec after the last frost in early November. Killed by autumn frost; often reseeds. |
| North Queensland | May to October | Dry season May to Oct. Nasturtium (annual) prefers cooler months. |
| Darwin & Top End | May to October | Dry season May to Oct. Nasturtium (annual) prefers cooler months. |
Not to be confused with: Watercress, whose botanical name is Nasturtium officinale. It is a different plant that grows in water. Garden nasturtium is Tropaeolum.
Where to plant
Nasturtiums flower best in sun and in poor to average, well-drained soil. Rich, well-fed soil gives masses of leaves and few flowers, so do not add fertiliser. They cope with part shade, which helps in hot summers, and they will scramble over the ground, spill from a pot or climb a fence.
They are frost tender. In frost-free coastal areas they grow through the cooler months and often self-seed. In frosty areas, sow after the last frost.
Choosing a variety
- Climbing or trailing types grow up to 2 to 3 m and suit fences, banks and large spaces.
- Dwarf or bush types (for example Tom Thumb types) stay compact for pots and edges.
- Variegated types such as Alaska have cream-marbled leaves.
How to plant
- Soak the large seeds overnight to speed germination, if you like.
- Sow directly where they are to grow, 1 to 2 cm deep and about 30 cm apart.
- Water in and keep just moist until the seedlings appear, usually in 7 to 14 days.
- Do not feed. Water only in dry spells once plants are established.
Watering and feeding
Water moderately and let the soil dry a little between waterings. Nasturtiums need no fertiliser at all; feeding them gives leaves instead of flowers.
Pruning and care through the year
- Pick flowers and leaves often to keep new growth coming.
- Pull out or cut back plants that sprawl too far, and pull unwanted self-sown seedlings while they are small.
- Check the plants for aphids and caterpillars. That is their job as a sacrificial crop: pull off and bin heavily infested stems.
Harvesting
Pick young leaves and open flowers at any time. Pick green seed pods while they are plump and still soft if you want to pickle them. Use leaves and flowers on the day you pick them.
Growing in pots
Nasturtiums are excellent in pots, troughs and hanging baskets. Use a pot at least 20 cm wide with an ordinary potting mix, do not feed, and choose dwarf types for small pots and trailing types for baskets.
Using it
- Leaves: peppery, like watercress or rocket. Use young leaves in salads, wrap them around fillings, or blend them into a pesto.
- Flowers: a mild peppery taste and bright colour for salads, butters and garnishes.
- Green seed pods: pickle them in vinegar as a substitute for capers, often called poor man's capers.
- Eat them in normal food amounts as part of a meal.
Saving seed
Saving seed is easy. Leave a few flowers to form seeds, let the seeds turn pale and wrinkled on the plant or after they drop, then collect them, dry them for a week or two and store them in a paper bag.
Companion planting
Nasturtium is a classic sacrificial or trap plant. It attracts aphids (especially black aphids) and cabbage white butterflies, which then leave nearby crops alone, and its flowers feed bees and hoverflies.
Good companions
- Cucumber Planted nearby as a sacrificial plant to draw aphids away from the vines.
- Zucchini Draws aphids and brings in bees to pollinate the flowers.
- Pumpkin Shares the sprawling space and brings in pollinators.
- Beans Lures black aphids away from beans.
- Fruit trees A living groundcover under fruit trees that shades the soil and brings in bees.
Pests and diseases
Nasturtiums are meant to attract some pests. Expect aphids and caterpillars, and treat that as a sign they are doing their job.
Pests to watch for
- Aphids Clusters of black or green insects on stems and leaf undersides. Pull off and bin badly infested stems.
- Caterpillars Holes in leaves from cabbage white butterfly caterpillars, which also feed on brassicas.
Diseases to watch for
- Mosaic virus Mottled, yellow-patterned and distorted leaves. Pull out affected plants.
Common questions
Can you eat nasturtiums?
Yes. The leaves, flowers and green seed pods are all edible and taste peppery, a little like watercress. Use them fresh in salads, pesto and garnishes, and pickle the green seed pods as a caper substitute.
Why does my nasturtium have lots of leaves but no flowers?
The soil is too rich or it has been fed. Nasturtiums flower best in poor to average soil with no fertiliser. Too much shade also cuts flowering.
Are nasturtiums good companion plants?
Yes, as a sacrificial plant. They attract aphids and cabbage white butterflies away from crops such as beans and brassicas, and their flowers bring in bees and hoverflies. Check them often and remove heavily infested stems.
Is nasturtium the same as watercress?
No. Watercress's botanical name is Nasturtium officinale, but it is a different plant that grows in water. The garden nasturtium is Tropaeolum majus. Both have a peppery taste.
When should I plant nasturtium seeds?
Sow in spring once frost has passed. In frost-free coastal areas you can also sow in autumn for flowers through winter and spring. Pick your region at the top of the page for the months.
How do I make nasturtium capers?
Pick green, soft seed pods and wash them well, then soak them in salty brine for two or three days. Rinse off the salt, pack them into a sterilised jar, pour over hot white vinegar with a little sugar, and seal. Keep the jar in the fridge once opened.
Sources we checked: Gardening Australia: Poor Man's Capers; RHS: Nasturtium; RHS: Nasturtium officinale (watercress).