Nasturtium, literally “nose-twister” or “nose-tweaker” as a common name, refers to a genus of roughly 80 species of annual and perennial herbaceous flowering plants in the genus Tropaeolum. They have showy, often intensely bright flowers and rounded, shield-shaped leaves with the petiole in the center. The intense color can make macrophotography quite difficult. The flowers have five petals and a funnel-shaped nectar tube in the back. The most common use of the nasturtium plant in cultivation is as an ornamental flower. It grows easily and prolifically, and is a self-seeding annual.
In cultivation, most varieties of nasturtiums prefer to be grown in direct or indirect sunlight, with a few preferring partial shade. All parts of the plant are edible. The flower has most often been consumed, making for an especially ornamental salad ingredient. It has a slightly peppery taste reminiscent of watercress, and is also used in stir fry. The unripe seed pods can be harvested and pickled with hot vinegar, to produce a condiment and garnish, sometimes used in place of capers, although the taste is strongly peppery.
Nasturtiums are also considered widely useful companion plants. They repel a great many cucurbit pests, like squash bugs, cucumber beetles, and several caterpillars. They have a similar range of benefits for brassica plants, especially broccoli and cauliflower. They also attract black fly aphids, and are sometimes planted in the hope of saving crops susceptible to them as a trap crop. They may also attract beneficial, predatory insects.