Nasturtiums (Tropaeolum spp) - How to Grow & Care Guide

Plant Snapshot

Common Name: Nasturtiums
Latin Name: Tropaeolum spp
Hardiness Zones: USDA zones 9–11 perennial where winter is mild otherwise grown as an annual. Frost sensitive.
Typical Height: Varies by type 6–118 in (15–300 cm) from dwarf bush types to vigorous trailing climbers.
Typical Spread: Variable 12 in to 71 in (30–180 cm) common for bush and trailing types. Some climbers trail farther.
Bloom Period: Late spring through first frost in many temperate gardens.
Soil Preferences: Well drained, average to poor fertility soils. High fertility or rich soil can reduce flowering.
Light Preferences: Full sun for best flowering. Tolerate light afternoon shade in hot climates.
Toxicity: Leaves and flowers are edible and generally regarded non toxic to pets. Use caution if plants were treated with pesticides.
Propagation: Easily grown from seed sown outdoors after frost or started indoors 3–6 weeks before last frost. Some types root from stem cuttings.

Key Facts

Tender annuals or short-lived perennials depending on climate.
Edible leaves and flowers with a peppery flavor.
Available in bush, trailing, and climbing habits.
Prefers well drained soil and moderate fertility.
Flowers from late spring through frost in many climates.
Best flowering occurs in full sun or with light afternoon shade in hot regions.
Grows easily from seed and is suitable for direct sowing.
Frost will usually kill plants so they are grown as annuals in cold climates.
Attractive to pollinators and beneficial insects.

Nasturtiums (Tropaeolum spp) are easy to grow ornamental and edible plants available as bush, trailing and climbing types. They flower from late spring through the first frost and are most often started from seed for quick color and salad ingredients.

Identification

Tender annuals or short lived perennials depending on climate with edible leaves and flowers that have a peppery flavor. Plants occur as compact bush forms or long trailing and climbing types with heights ranging from about 15 to 300 cm and spreads commonly from 30 to 180 cm depending on cultivar.

Where to grow and best uses

Grow in full sun for best flowering while allowing light afternoon shade in hot regions. Use bush varieties in borders and small beds, trailing types in hanging baskets and over walls, and climbers on a simple support. Attractive flowers also draw pollinators and beneficial insects.

Planting time and propagation

Direct sow outdoors after danger of frost or start indoors about three to six weeks before the last frost. Seeds germinate readily and establish quickly. Space plants relative to their mature spread with compact types closer together and trailing or vigorous types given room to trail.

Soil, light and watering

Prefer well drained soil of average to low fertility because rich soils promote foliage at the expense of blooms. Full sun produces the most flowers though light afternoon shade helps in very hot areas. Avoid waterlogged conditions which reduce flowering and can harm roots.

Containers and training

Suitable for containers, window boxes and hanging baskets with compact cultivars for small pots and trailing cultivars for baskets and edges. Climbers will use simple trellises or supports and can be trained to cover low fences or walls where space allows.

After flowering and winter care

Blooms continue until frost in many climates. Frost usually kills plants so they are treated as annuals outside cold zones. In USDA zones 9 to 11 plants may persist or self seed. Remove frost killed plants or leave seed heads to self sow for volunteers next year.

Controlling spread and naturalizing

Nasturtiums will self seed readily where allowed which can lead to naturalizing in favorable sites. To limit reseeding collect or discard seed pods before they open. To encourage volunteers allow seeds to ripen and drop where you want new plants the following season.

Frequently asked questions

How fast does Nasturtiums grow?: Seeds germinate quickly and plants can reach flowering size within a single season when sown after frost, with final size depending on cultivar habit.
Are nasturtiums edible?: Yes. Leaves and flowers are edible and have a peppery flavor. Confirm no pesticide residues before eating.
Can nasturtiums be perennial?: They are perennial in mild climates such as USDA zones 9 to 11. In colder zones they are usually grown as annuals because frost kills them.
When should I sow nasturtium seed?: Sow seed outdoors after danger of frost or start indoors three to six weeks before the last frost for earlier blooms.
Do nasturtiums need rich soil?: No. They perform best in well drained soils of average to low fertility because overly rich soil can reduce flowering.