Edible Landscaping - Edible of the Month: Nasturtium

Bright yellow nasturtium flowers rise above the foliage for a cheery display in the garden.

In the world of edible annual flowers, nasturtiums are one of the tastiest and easiest to grow. Nasturtiums grow quickly from seed and, depending on the variety, can be grown as climbers on fences and trellises or as bushy plants in a window boxes and containers. Although treated as annuals, these fast growing plants are technically herbaceous perennials. In frost-free areas of the South and West they grow so vigorously that many people consider them weeds.

The biggest surprise with nasturtiums is the taste. In Latin nasturtium literally means "nose twist." While most edible flowers have a subtle flavor, nasturtiums knock your socks off with their peppery taste. Plus, it's not just the flowers and buds that are packed with a zippy flavor; the young leaves are tender and edible as well. Nasturtiums are popular with chefs and home gardeners because their colorful flowers not only dress up a plate, they're high in vitamins A, C (10 times as much as lettuce), and D.

While there are several species of nasturtiums, most popular varieties are one of two common species. Tropaeolum majus is a trailing type that can be trained to climb. Tropaeolum minus is a bush type. Nasturtium flowers range from pastels, such as pale yellow, to vibrant oranges and reds, and are available in single or double flowers. You can purchase seed mixes that produce plants in a variety of flower colors, or single-color packets. Most modern varieties have been bred so the flowers stand above the foliage, making them especially striking in the garden.

Here are some of the best selections:

• 'Apricot Twist'. The vines of this trailing variety grow 3 to 4 feet long and the camellia-like double flowers are apricot-orange splashed with raspberry red.
• 'Empress of India'. This semi-bush selection produces 1- to 2-foot vines and features large, bright scarlet flowers that contrast well with the blue-green leaves.
• 'Hermine Grashoff'. The vines of this trailer grow 3 to 4 feet long and produce red-orange, camellia-like double flowers.
• Jewel of Africa mix. This 4- to 6-foot-long trailing mix includes yellow, red, cream, and pink flowers with unique variegated leaves.
• 'Moonlight'. The vines of this trailer grow up to 7 feet long and produce unusual, pale yellow flowers.
• 'Night and Day'. This mix produces compact plants with 12-inch vines and flowers in both white and deep red.
• 'Peach Melba'. This bush variety has cream flowers with a raspberry red throat.
• 'Salmon Baby'. The flowers on this bush variety are a striking shade of salmon.
• 'Strawberries & Cream'. This bush variety features flowers in pale yellow with splashes of strawberry red.
• Tall Trailing mix. The vines of this vigorous trailer grow 8 to 10 feet long. Flower colors include rose, yellow, and orange.
• Tip Top Alaska mix. The vines of this bush-type mix grow just 10 inches long. Flower colors include yellow, crimson, orange, cherry, and salmon, held above variegated foliage.
• Whirlybird mix . This bush variety is available as a mix of flower colors, or in separate colors, including cream, salmon, gold, and cherry rose. The flowers are semi-double.

The mounded shape of nasturtiums makes them a nice border plant, and the water lily-like leaves are as edible as the bright flowers.

Nasturtiums flower best in full sun, but still grow well in partly shaded locations, especially in hot-summer areas. They love cool, damp, well-drained soil. If plants begin to flag in the heat of summer, cut them back and they'll regrow and flower again when cooler weather arrives in fall.

Nasturtiums thrive on neglect and don't require rich soil. In fact, if you amend soil with too much nitrogen-rich fertilizer or manure, you'll get lots of dark green foliage and few flowers. In all but the richest soils, amend the planting area by mixing in a 1-inch layer of compost. Plants shouldn't need supplemental fertilizing during the growing season.

Nasturtiums are available in flower colors ranging from the palest yellow to the deepest red.

Nasturtium seeds are large and easy to handle. Sow seeds 10 to 12 inches apart in the garden about a week before the last frost date for your area. Seedlings can also be started indoors, but their taproots make them difficult to transplant. If you do grow them indoors, start them in peat pots. When roots show through the pots' drainage holes, transplant the seedlings, peat pot and all, into the garden.

After sowing, keep the bed well watered and weed-free, and within two months you'll see vigorous growth and abundant flowers. Nasturtiums are relatively trouble-free. Aphids may feed on the new leaves and flowers. Wash these soft-bodied insects off the plant with frequent sprays of water or use insecticidal soap.

Beautiful 'Peach Melba' nasturtium flowers are a delight in any garden or salad.

For salads, harvest nasturtium flower buds, flowers, and young leaves in the cool of the morning when flowers have just opened. The more heat-stressed the plant, the more pungent the leaves and flowers will taste. Gently wash and dry the flowers and leaves and use immediately or store in a plastic bag in the refrigerator. Although you can eat the whole flower, if the flavor is too strong use only the milder-tasting petals.

You can also use nasturtiums in stir-fries, cook them with pasta, and stuff the flowers. More ambitious cooks can try grinding the seeds to use as a pepper substitute and in flavored oils, and pickling the flower buds or immature seedpods to use as a substitute for capers.

Stunning Compact Nasturtium

Growing Edible Flowers

About Charlie Nardozzi

Charlie Nardozzi is an award winning, nationally recognized garden writer, speaker, radio, and television personality. He has worked for more than 30 years bringing expert gardening information to home gardeners through radio, television, talks, tours, on-line, and the printed page. Charlie delights in making gardening information simple, easy, fun and accessible to everyone. He's the author of 6 books, has three radio shows in New England and a TV show. He leads Garden Tours around the world and consults with organizations and companies about gardening programs. See more about him at Gardening With Charlie.