We have known for a long time that certain flowers are edible. Violas, herb flowers of many kinds, and daylilies all have their uses in the kitchen. But our all-time favorite edible flower is the old-fashioned nasturtium. It tolerates poor soil, and actually performs best in low nitrogen soils. Its real value, however, lies in the fact that the leaves are edible as salad or cooked greens, and they are available from late spring through the first killing frost.
Nasturtium, botanically Tropaeolum majus, is a member of the cabbage family. No surprise, then, that the flavor is reminiscent of cauliflower or kale. All parts of the plant are edible. The flowers contain about as much vitamin C as an equal amount of parsley, and they have the highest lutein content of any edible plant. Presumably the leaves are similar in terms of vitamin C content. Lutein is a yellow pigment, so it is probably not as abundant in the leaves as in the flowers. In humans, lutein is thought to play a role in protecting the retina from damage by sunlight.
The large seed pods of nasturtium can also be harvested. Do this while they are still green. Drop them into a bottle of vinegar and let them sit a week or two, then use them like capers.
Nasturtium plants typically stop growing during the hottest days of summer, surging back again as soon as the weather cools down, and then growing luxuriantly until frost kills them. You can find the seeds on almost every seed rack in spring. Just scatter them where you want the plants to grow. In subsequent years, the plants should return from self sown seed. Look for seedlings around the first of May. Popular cultivars include 'Jewel,' 'Whirlybird,' 'Empress of India,' and 'Alaska.' The last one has variegated leaves, making an especially attractive display in the garden or on a salad.
Next spring, why not include a patch of nasturtiums in your edible garden? You'll enjoy them all season long.