Gardening Articles: Flowers :: Annuals
Durable, Delectable Nasturtiums (page 3 of 3)
by Charlie Nardozzi
Adding flowers to food has long been a custom in many cultures around the world. For centuries, Chinese cooks have used lotus, chrysanthemum, and lily flowers or buds in their recipes. American colonists added marigolds to mutton broth. Nasturtiums, among the best-known edible flowers, are popular with chefs. Not only do they dress up a plate, but they're high in vitamins A, C (10 times as much as in lettuce), and D. The leaves, flowers, buds, and seeds are all edible, with a peppery flavor that adds a zing to any dish.
Before harvesting a whole patch of nasturtiums, taste a few flowers first. Their flavor may vary depending on the plant, and on soil and weather conditions. Generally, the more stressed a plant is (by lack of water or nutrients, or exposure to adverse weather), the more pungent its flavor.
When harvesting the leaves, select young, tender ones. Harvest buds or fully opened flowers in midmorning, ideally on a cool day. The entire blossom is edible, but if you find the organs inside the petals to be bitter, you can remove them with scissors. Gently wash and dry the flowers and leaves, and store them in a plastic bag in the refrigerator.
In the kitchen, add the flowers to salads and stir-fry dishes. You can also stuff them and cook them with pasta. More ambitious cooks can try grinding the seeds for use as a pepper substitute, griding them for oil, or pickling the flower buds or immature seedpods and use as a substitute for capers.
Growing Unusual Perennial Nasturtiums
Several trailing and climbing species of Tropaeolum have unusual flower and leaf forms. However, they're hard to find and harder to grow (especially from seed) because they're adapted only to particular growing conditions. To grow best, these types require mild winters (hardy to zone 7) and cool, humid summers similar to those in England. Or grow them in a cool greenhouse. They like a location in part shade to full sun and prefer their roots be kept moist and cool. Most climbers twine around a support. The aggressive types grow well over trellises or pergolas.
The easiest of these nasturtiums to grow is T. tuberosum. Started from a tuber, it produces a vigorous 15-foot vine with 2-inch-diameter orange-and-yellow flowers. The flowers don't bloom until fall, but the three-lobed, partly divided foliage makes this vine attractive even when it's not blooming. In climates colder than zone 7, the edible tubers can be lifted in fall and stored in winter as you would dahlias. For an earlier-blooming variety, try 'Ken Aslet'.
Scotch flame flowers (T. speciosum). are relatively easy to grow and are available as plants. The 6-foot vines with ferny leaves produce 2-inch vivid scarlet lobelia-like flowers for several weeks in July. They aren't as aggressive as T. tuberosum, but they do spread by roots as deep as 2 feet, so they can become invasive.
Wreath nasturtium (T. polyphyllum) is available only from seed. The 3- to 4-foot vine grows from a rhizome (an underground stem) and produces beautiful gray-blue leaves and 1-inch golden yellow cup-shaped flowers. The plant blooms for only two to three weeks in early summer, then dies back until the next spring. Wreath nasturtium is best used as a low-growing rock garden plant because the leaves and flowers stand only about 3 inches tall.
T. tricolor is the most difficult to grow of the four. Furthermore, it's available only from seed. The fragile 3-foot-long vine produces spurlike yellow-centered, orange-red blooms fringed in purple.
Charlie Nardozzi is senior horticulturist at National Gardening Association.
Photography by Suzanne DeJohn/National Gardening Association