The resurgence in interest in growing old-fashioned flowers has helped the nasturtium make a comeback in cottage gardens. The flowers have a delicate fragrance that many people will remember from grandma's garden. Nasturtiums (Tropaeolum majus) are attractive, dependable garden plants that produce round, bright green leaves and blooms in several colors, all with distinctive, long spurs. The flowers and leaves of these easy-to-grow plants are also edible. The leaves are rich in vitamin C and have a peppery flavor, while the flowers make a different and colorful addition to salads and other dishes.
Nasturtiums come in three types: dwarf, semi-trailing, and single flower climbing. Dwarf types are bushy and compact and include the cultivars 'Alaska', 'Empress of India,' 'Strawberries and Cream,' and 'Whirlybird.' Semi-trailing types reach a length of two to three feet, making them ideal for hanging baskets. The Gleam series is a good choice here, having been named an All-America Selections winner in 1935.
Nasturtium is one of the easiest flowers to grow from seed. The best flowering will be in full sun, but they will tolerate partial shade. Seeds can be sown directly in the garden beginning in late May or started indoors to get a good head start on the season. However, as nasturtiums do not fare well when transplanted, use peat pots and plant these directly in the soil. Nasturtiums are not choosy about their soil, but, given a choice, do prefer a light, sandy soil. Don't spoil them with rich, fertile soil and fertilizers as this will only result in lush foliage and few blooms. The large seeds of nasturtiums are easily held by tiny fingers, making them a good flower for children to help plant. In addition, the seeds germinate quickly and plants grow rapidly, so children can see the results of their nurturing soon. Only a small space is needed to provide a child with his or her own garden. Even a single foot square container can become a spring-to-fall garden. In the early spring, sow fast growing seeds like lettuce and radishes with the nasturtiums. By the time they are harvested, the nasturtiums will be ready to bloom until fall.
Although most often grown as annuals, nasturtiums are, botanically, herbaceous perennials; that is, they die to the ground in fall and grow again the next spring. In frost-free areas such as coastal California and in Las Vegas where I live and garden they grow like weeds, with 6-inch diameter leaves atop 20-foot-long stems sprawling year-round. A few lesser-known species are perennial to USDA Hardiness Zone 7, and although they're a challenge to grow, they offer gardeners unique flower and foliage forms.
Nasturtiums grow well in sun or partially shaded locations. For best flower production, plant your nasturtiums in full sun. The plants prefer moist, well-draining soil and tolerate damp locations quite well. They do well in all soil types but benefit from addition of compost at planting time. Adding fertilizer is unnecessary, and using high-nitrogen types may stimulate growth of leaves over flowers. You can direct-sow nasturtium seeds outdoors after warm weather has arrived. If you start seeds indoors, place seeds in individual peat pots to minimize transplant shock to their long taproots when you move them outdoors. If your plants begin to look leggy and produce fewer flowers during hot summer days, cut them back and they'll produce new growth and a second crop of flowers.
When you're choosing varieties to grow, first decide whether you want bush or trailing kinds. Consider the unusual double flowers of the camellia-like types, too. In addition, some varieties have variegated foliage that's attractive even when the plant is not flowering. The accompanying chart provides more details about the best varieties.
Trailing Nasturtiums. These nasturtiums have bigger flowers and leaves but don't produce as many flowers as the bush varieties do. They look great in hanging baskets, sprawling on a bed like a ground cover, or cascading over the edge of a raised bed. A vigorous trailing type, such as 'Tall Trailing Mix', can be trained on a fence as a climber. I plant this variety between tepees sorting pole and scarlet runner beans, and by midsummer I have a striking tepee of multicolored nasturtium flowers and delicious scarlet runner and pole beans to harvest and enjoy. 'Jewel of Africa Mix', another notable trailing type, features variegated leaves and a colorful combination of flowers.
Bush Nasturtiums. My favorite bush type is the variegated 'Tip Top Alaska Mix', an improved selection from the original 'Alaska' variety. Although it's not as floriferous and vigorous as other bush varieties, the vivid leaf markings more than make up for the meager flowering. Bush-type nasturtiums look great in window boxes and containers, or edging a path or border.
Whirlybird, offer a variety of flower colors, some of my favorites are the single-colored varieties. The scarlet flowers of 'Empress of India' contrast beautifully with its blue-green leaves. Although listed as a bush form, this one tends to trail to 1 to 2 feet long. 'Moonlight' (yellow and trailing) and 'Salmon Baby' (salmon with bush habit) offer more dramatic single-hued flower color.
Double Flowers. The most unusual varieties actually aren't new: They are rediscovered heirlooms dating back to the late nineteenth century. They look much like camellias or dahlias, so you'd be hard-pressed to recognize these flowers as nasturtiums. 'Apricot Twist' (apricot splashed with red) and 'Hermine Grashoff' (red) are two trailing types that don't form seeds and are available only as rooted cuttings. These nasturtiums aren't as vigorous as other trailing types and grow better in hanging baskets or containers. They are hard to find, I bought mine at Select Seeds.
Dwarf Nasturtiums. Generally grown as annuals, nasturtiums may survive winters in milder regions, where they can grow as perennials. Many common varieties of nasturtiums are dwarf plants that have a bushy, compact growth habit, making them quite useful in border plantings or for the front portion of a garden bed. Dwarf nasturtiums also make attractive additions to window boxes or patio pots. Dwarf cultivars include "Peach Melba," with creamy flowers that have throats of raspberry red; "Strawberries and Cream," with pale yellow flowers that have splashes of rosy pink and red; and the "Whirlybird" mix, producing bushy plants with a variety of flower colors that include salmon, yellow, orange and cream.
Semi-trailing Types. All nasturtiums have a tendency to grow in a vining habit, but, unlike in dwarf varieties, this has been suppressed only partly in the semi-trailing types. These nasturtiums grow as vines that reach a length of 2 to 3 feet and do well as trailing plants in hanging baskets. They can also grow successfully in pots when provided with a short trellis. Examples of this type include "Empress of India," with 1- to 2-foot-long vines, bright scarlet flowers and bluish-green leaves; "Night and Day," with 1-foot-long vines and flowers in both red and white; and the "Tip Top Alaska" mix, with variegated leaves, 10 inch-long vines and flowers in yellow, red and orange.
‘Jewel of Africa’
Tall Climbers. Many nasturtium varieties grow in a long, vining habit, climbing to heights of 8 or 10 feet when given support or trailing along the ground when support is unavailable. These plants are good choices for arbors, tall trellises or along fences. "Jewel of Africa" mix belongs to this group, producing 4- to 6-foot-long vines covered with variegated leaves and red, yellow, pink or cream flowers. "Apricot Twist" produces 3- to 4-foot-long vines and double flowers resembling camellias in apricot or orange with red blotches. Another trailing group is called the "Tall Trailing" mix, with 8- to 10-foot-long vines, variegated foliage and flowers in yellow, salmon, orange or red.
(Tropaeolum majus 'Strawberry Ice') bears deep yellow flowers with a strawberry-red blotch at the base of each petal. It trails or climbs to 16 inches.