Nasturtium plants (Tropaeolum spp.) are loved for their rich, saturated, jewel-toned colors. Planted in the spring after the threat of frost has passed, they are fast and easy to grow. In fact, they do best with a little neglect. There are nasturtium varieties for almost every gardening purpose: bushy plants for borders and edges, trailing plants for walls and containers, and climbers to add dramatic height. Plus, the leaves and flowers are edible, with a peppery tang, and even the seed pods can be used as a substitute for capers.
Nasturtium plants grow full, with lots of bright green leaves and spots of brightly colored blossoms poking out of the masses of foliage. Their leaves are rounded like those of a water lily, and the flowers have an open funnel shape with a little claw or spur on the underside. These flowers can vary in shade, but the most popular versions are yellow, orange, pink, red, or mahogany. There are also varieties in subdued shades of butter yellow and cream, as well as varieties with variegated leaves.
|Plant Type||Annual flower|
|Mature Size||1 to 10 feet tall and 1 to 3 feet wide|
|Sun Exposure||Full sun|
|Soil Type||Average, medium moisture, well-draining|
|Soil pH||6 to 8|
|Bloom Time||May to September|
|Flower Color||Red, orange, pink, yellow, cream|
|Hardiness Zones||2 to 11 (annual)|
|Native Area||Central and South America|
How to Grow Nasturtiums
Nasturtiums are usually started from seed as annuals, so you won’t often find them available as plants at nurseries. However, the seeds germinate quickly, and the plants will be up and blooming in no time.
Seeds can be sown directly in the garden when the soil has warmed or started indoors about two to four weeks earlier. Nasturtiums don’t especially like being transplanted, so starting indoor seedlings in peat or paper pots can help to reduce transplant shock. And once they're planted, they largely take care of themselves, rewarding you with their beautiful flowers and foliage. Deadheading (removing spent blooms) is usually not necessary unless a plant has been stressed and is holding on to the old blooms.
Nasturtiums will spill beautifully over walls and onto pavers when used as edging plants. They also hold up well in containers. Climbing varieties will amble up and through shrubs. Bushy, ground-hugging nasturtiums will fill in blooming gaps among complementary colored daylilies and roses. Plus, you can use clusters to brighten up the vegetable garden.
One factor to be aware of when choosing which species of nasturtium to grow is that the ample foliage of some varieties can obstruct their flowers. If you are growing your nasturtiums at ground level, choose a variety that holds its flowers above its leaves, so you can easily see them.
Nasturtiums will grow and bloom best in full sun. But they can tolerate a little shade and might actually prefer shade from the hot afternoon sun in warmer climates.
These flowers do well in average soil with good drainage. They can somewhat tolerate dry soil, though a moderate amount of moisture is appreciated.
Nasturtiums typically prefer weekly watering. They will survive some drought conditions, but flowering will likely diminish and the foliage can begin to look ratty.
Temperature and Humidity
Some varieties of nasturtiums are perennial in USDA growing zones 9 through 11. However, most are treated as annual plants, completing their life cycle in one season. Plant them after the last frost in the spring, and you should be able to enjoy them until frost arrives again in the fall. In addition, these plants generally prefer average humidity levels, though they're not overly particular. But they can struggle in very dry or very humid conditions.
You likely won't have to feed nasturtium plants at all during the growing season unless you have very poor soil. They thrive in lean to average soil, and fertilizer can cause them to put out more foliage and fewer flowers.
Common Pests and Diseases
Nasturtiums are prone to aphids and consequently are sometimes used as a trap crop in vegetable gardens. If a plant's foliage looks crinkled or otherwise unhealthy, aphids might be the problem. Also, many ants on the plant also can be a sign of aphids, as the ants feed on the aphids’ sticky secretion. A strong blast of water is usually enough to get rid of aphids before you turn to insecticides.
Varieties of Nasturtiums
There are dozens of species of nasturtiums, including:
- 'Alaska' Series: These are bushy dwarf plants with heavily variegated foliage and blossoms above the foliage.
- 'Jewel' Series: This series includes bushy dwarf plants with double and semi-double blooms. They're profuse bloomers, but the flowers tend to get lost under the foliage.
- 'Peach Melba': These bushy dwarf plants with semi-double buttery yellow flowers splashed with orange-red centers are good for containers.
- 'Canary Creeper': This is a perennial vine within the nasturtium genus that has yellow flowers that look like a bird’s wings.