Native to South and Central America, nasturtiums are rugged plants that provide lovely edible blooms.
The history of nasturtiums
When nasturtiums arrived in Spain in the 1500’s, they were called “Indian cresses” because of their peppery flavor and their use in salads. Nasturtium flowers have been gracing gardens since Roman times. Back when the Romans defeated an army, they would set up a trophy (tropaeum) pole on which they would hang the shields and helmets of the losers. Nasturtiums (Tropaeolum) earned their Latin name because, to Carl Linnaeus*, the rounded leaves reminded him of shields and the flowers looked like blood-stained helmets. (The word nasturtium literally means “nose tweaker”.)
The botany of nasturtiums
Nasturtium are perennial and annual dicotyledons, depending on the variety and local conditions. There are climbing and bushy nasturtiums. Nasturtium stems are somewhat succulent and the roots can be tuberous. One particularly rugged variety from Chile, T. polyplyllum, survives at altitudes of 10,000 feet! (Most of us would be out of breath and a bit wobbly at that elevation!)
Nasturtium flowers can be yellow, orange, reddish-brown, white, red, or even blue. Flowers have five clawed petals, with the bottom three looking different from the top two. Each bisexual flower has 8 whorled stamens. Nasturtium seeds look like naked nuts with three segments. Leaves may be rounded or deeply lobed. Leaf stems tend to be rather long. There are about 80 species of nasturtiums. Nasturtium are the only members of their genus.
How to grow nasturtiums
Until recently, it was believed that nasturtium seeds required scarification (damage to the seed hull) for germination to occur. We now know that this is not true. Seeds can be planted directly in the ground after the final frost date. Seeds should be planted 10-15” apart and 1” deep. Water regularly, unless a drought-tolerant variety is selected. Nasturtiums prefer well-drained or sandy soil. They perform best in full sun or partial shade. Once nasturtiums are established, you can easily end up with far more plants than you need. When this happens, simply transplant seedlings into a nice little container and gift them to family and friends!
Uses of nasturtiums
All parts of the nasturtium plant are edible, but most people only eat the flowers. The flowers look lovely in salads and add a nice peppery flavor to stir-fry. Nasturtium flowers contain the highest amount of lutein of any edible plant. Lutein is an antioxidant that protects the retina from free-radical damage by blue light, helping prevent macular degeneration. Unripe seed pods can be pickled in spiced vinegar and used like capers. The tuber of the Mashua variety (T. tuberous) is used in the Andes as a major food source.
In herbal medicine, nasturtiums are used for their expectorant and antiseptic qualities. They are believed to promote the formation of new blood cells and to relieve chest colds.
Nasturtiums attract butterflies and other pollinators. They can also be used in companion planting as target plants, to distract pests such as cabbageworms and mites away from more vulnerable plants. Nasturtiums are believed to repel Asparagus beetles, squash beetles, aphids, Mexican bean beetles, cabbageworms, and whiteflies.
Nasturtiums readily self-seed and they take little or no care once established. Add these lovelies to your garden or windowsill for some bright, flavorful blooms!
* Carl Linnaeus created our modern system of naming plants and animals in something called binomial nomenclature.
You can grow a surprising amount of food in your own yard. Ask me how!