How to Plant and Grow Nasturtium

Nasturtium is a fast-growing heirloom annual with slightly succulent stems and distinctive, rounded green leaves that resemble miniature lotus leaves. Some varieties even have variegated leaves marked with white or cream. Cultivars are mounding, some are trailing, and others are climbers. The flowers have a funnel shape with a short spur off the back, and come in a range of warm colors from creamy yellow to bright red. Adding the edible blossoms to salads or other dishes adds color and a light, peppery flavor. The large seeds can be pickled and used as a substitute for capers.

Where to Plant Nasturtium

Nasturtiums are easy to grow and work well in both garden beds and containers. They perform well as edging plants or as fillers among perennials. Since they have some pest deterrent properties among cabbage, broccoli, and cauliflower plants, nasturtiums are also welcome plants in the vegetable garden. Vividly colored blossoms pop against the gray-green foliage for an impressive effect when planted in large groups. Much like beans in a vegetable bed, nasturtiums fall into a bush or vine category and need to be planted accordingly. Whether you opt for a bush or vine type, they grow best in full sun.

How and When to Plant Nasturtium

Plant nasturtiums in the spring after all danger of frost has passed. To plant nursery specimens or seedlings, dig a hole about the same width and depth as the planting container. Remove the plant and loosen the roots a bit from the root ball before placing in the hole. Backfill with soil, tamp lightly, and water well.

When planting several nasturtiums, space them 12 inches apart.

Nasturtium Care Tips

Light

Choose a planting site that receives at least 6 hours of bright sunlight a day for best blossoms. While nasturtium can tolerate partial shade, flowering won't be as profuse. That said, in warmer climates, the plants will benefit from some protection from hot afternoon sun.

Soil and Water

Although there are several species of nasturtium with varying requirements, the most commonly grown annual species do best when directly seeded in well-drained soil, and they prefer regular watering. During droughts, they're prone to wilt, but once watered they bounce right back. If you plant nasturtiums in soil too rich in organic matter, the plants become floppy and produce fewer flowers because the excess nutrients are going toward growing new leaves.

Temperature and Humidity

Nasturtiums bloom best in the cooler temperatures of spring and fall. They aren't fussy about humidity but the plants will struggle in extreme humidity or very dry conditions. Nasturtiums can tolerate a light frost but will die after a freeze.

Fertilizer

Nasturtiums do not require feeding and, unless soil conditions are especially poor, don't need soil amendments to thrive—in fact, a rich soil will often spur foliage growth at the expense of flowers. Since nasturtiums are often used in food preparation, a hands-off approach to synthetic additives is best.

Pruning

Generally, nasturtiums do not need to be deadheaded but picking leaves and flowers for use in the kitchen will keep the plant looking bushy and attractive. By midsummer, vining types may need to be cut back to avoid leggy growth. Trim off at least 12 inches to stimulate the plant.

Potting and Repotting Nasturtium

Nasturtium makes a good potted plant, either on its own or as part of a mixed container with other plants that have similar cultural needs. Select a pot with large drainage holes and use well-draining potting soil. Keep in mind that potted plants, unlike plants in the landscape, require more frequent watering.

Pests and Problems

Nasturtiums are attractive to aphids. If you see these little bugs on your plants, and you're not suing them as a buffer for your vegetable garden, a good blast of water from the hose should dislodge them.

Bacterial leaf spot may also appear in less-than-ideal conditions. Minimize the chance of this disease with proper air circulation among plants and by watering them at soil level rather than by overhead spray.

Nasturtiums are not attractive to either rabbits or deer.

How to Propagate Nasturtiums

Nasturtiums are ordinarily grown from seed but can also be propagated via stem cuttings.

To grow from cuttings: Fill a shallow tray with a lightly dampened sterile seed-starting mixture. Use sharp bypass pruners to cut 4-inch-long plant cuttings with at least two sets of leaf nodes. Pinch off flower buds and remove the lower leaves. Plant the cut end of the branch in the pre-mixed seed-starter after dipping it in rooting hormone. Place it in bright indirect light or under grow lights. Rooting should take place within about a week. When roots are strong, transplant them to planters filled with potting mix or outdoors.

To grow from seed: You can start nasturtium seeds directly in the garden after the soil has warmed to at least 55-65 degrees F, or indoors in peat pots (to minimize transplant shock) two to four weeks before the average last frost date in your area. Plant seeds ½-inch deep and keep soil moist. Seeds should germinate in 7 to 10 days.

Types of Nasturtium

Nasturtiums are a beloved old-fashioned plant associated with cottage gardens, but there have been several newer developments. Much of nasturtium breeding has centered on creating more garden-friendly plants, typically bush-type annuals. There are also many varieties with variegated foliage. Some of the most exciting developments revolve around color, introducing new hues and developing ones that change, for example, opening as light peach and fading into deep red. Here are some tried-and-true types to try.

'Alaska' Nasturtium

Tropaeolum majus 'Alaska' is a trailing variety reaching 12 -15 inches. It offers exciting, white-splashed foliage and striking red, orange, gold, yellow, and salmon flowers.

Canary Creeper

This selection of Tropaeolum peregrinum in late spring offers abundant fringed canary-yellow blooms that appear almost like butterflies. It climbs to 15 feet and is perennial in Zones 9-10.

'Empress of India' Nasturtium

Tropaeolum majus 'Empress of India' bears velvety, crimson-red flowers on a compact, 14-inch-tall plant.

'Jewel of Africa' Nasturtium

This variety of Tropaeolum majus is a climbing annual to 5 feet tall that has variegated foliage and blooms in red, gold, yellow, cream, or peach.

'Peach Melba' Nasturtium

Tropaeolum majus 'Peach Melba' offers salmon-peach flowers all summer long on compact, 1-foot-tall plants.

'Strawberry Ice' Nasturtium

This Tropaeolum majus selection bears deep yellow flowers with a strawberry-red blotch at the base of each petal. It trails or climbs to 16 inches.

Nasturtium Companion Plants

Petunia

Petunias are failproof favorites for gardeners everywhere. They're vigorous growers and prolific bloomers from midspring through late fall. Color choices are nearly limitless, some with beautiful veining and intriguing colors. Many varieties are sweetly fragrant (to be sure, check for aroma in the garden center.) Some are also touted as "weatherproof," which means that the flowers don't close up when splashed by water. Wave petunias have made this plant even more popular. Reaching up to 4 feet long, they're great as a groundcover or cascading from window boxes and pots. All petunias do best and grow more bushy and full if you pinch or cut them back by one- to two-thirds in midsummer.

Cosmos

You can depend on this cottage-garden favorite to provide color all season long. The simple, daisy-like flowers appear in cheery shades on tall stems that are great for cutting. The lacy foliage makes a good backdrop for shorter plants. Cosmos often self-seeds in the garden, so you may only have to plant it once, though the colors can appear muddy or odd in the self-seeders. Plant cosmos from seed directly in the ground in spring, or start from established seedlings. This flower doesn't like fertilizing or conditions that are too rich, which result in large and lush foliage but fewer blooms. It does best with average moisture, but will tolerate drought.

French Marigold

Just as you'd expect from something called French, these marigolds are the fancy ones. French marigolds tend to be frilly and some have a distinctive "crested eye." They grow roughly 8-12 inches high with a chic, neat, little growth habit and elegant dark green foliage. They do best in full sun with moist, well-drained soil and will flower all summer long. They may reseed, coming back year after year in spots where they're happy.