By Dr. Mercola
More than just a colorful flower that is easy to grow, nasturtium is valued as a tasty, edible plant known for its peppery tang. As the name suggests, you can be “nasty” to nasturtiums because they do well in lean soil and thrive when somewhat neglected. Whether you are looking for nasturtiums to add color to salads and party trays, act as a trap plant in your garden or cover an arch or trellis, there is certain to be a nasturtium variety suited to your need.
Plus, all parts of the plant can be used medicinally. Because nasturtiums are most often grown from seed, you may have trouble finding them at nurseries. The seeds germinate quickly, however, and since you’ll want to raise pesticide-free plants, your best option is to plant your own. Here’s everything you need to know to successfully grow nasturtiums.
An Andes Antibiotic: The History of Nasturtium
Nasturtium (Tropaeolum majus) is a flowering plant originating from South America whose name literally means “nose-twister.” It’s important to make a distinction between this type of nasturtium and Nasturtium officinale, which is commonly known as watercress. Natives of the Andes region used nasturtium as a general antibiotic, as well as to treat kidney problems and urinary tract infections.1 Because the plants are undemanding and can survive in lean soil, they were able to thrive in the rocky soil of the Andes Mountains.
The first nasturtium plant made its way to Europe in 1569 courtesy of Spanish physician and botanist Nicolás Monardes, who wrote extensively about the plants and animals he came in contact with while visiting South America.2 From there, nasturtiums became naturalized in parts of Africa, Asia, Europe and the U.S. Wherever they have been introduced, nasturtiums have been embraced for their cheerful blooms, culinary uses and medicinal value.
Nasturtiums Are a Great Source of Vitamin C, Lutein and More
Nasturtium flowers contain about 130 milligrams (mg) of vitamin C per 100 grams (g), or 3.5 ounces. Notably, nasturtiums boast the highest lutein content — 45 mg per 100 g serving — found in any edible plant.
The importance of lutein for your eye health was noted by researchers, who said, “As increasing evidence supports the role of lutein and zeaxanthin in reducing the risk of cataract and macular degeneration, food sources of these carotenoids are being sought.”3 According to the Urban Cultivator, nasturtiums are more than just a pretty flower; they have well-known medicinal properties:4
“Both the leaves and petals of the nasturtium plant are packed with nutrition, containing high levels of vitamin C. It has the ability to improve the immune system, tackling sore throats, coughs and colds, as well as bacterial and fungal infections. These plants also contain high amounts of manganese, iron, flavonoids and beta carotene.”
Further building the case for the nutritional value of nasturtium plants, The Kansas City Star states:5
“In traditional medicine, an ointment is made from nasturtium flowers and used to treat skin conditions, as well as hair loss. The group of phenols in the pigments of orange and red flowers helps [neutralize] the damaging effects of free radicals, thereby helping to protect us from chronic diseases such as cardiovascular disease and cancer.”
If taken during early pregnancy, nasturtiums might induce menstruation and cause a miscarriage.6 As such, it’s best to avoid eating any part of the nasturtium plant — capers, flowers, leaves and stems — during pregnancy. Additionally, even though nasturtiums were used for kidney and urinary tract problems in ancient times, be sure to consult your physician before using this plant for health purposes.
How to Spot Nasturtiums
Throughout history, the colorful blooms of nasturtiums have been embraced by artists, kings, presidents and ordinary gardeners. Impressionist artist Claude Monet featured nasturtiums in his artwork and garden in Giverny, France, where they continue to be grown annually.7
After nasturtiums made their way to North America from Europe, Thomas Jefferson grew them at Monticello.8 Reportedly, salads were a large part of his diet. While some varieties of nasturtiums are perennial in U.S. Department of Agriculture hardiness zones 9 to 11, most are grown as annuals going from seed to seed in a single season. You can recognize nasturtiums based on the following characteristics:9
- Massive foliage characterized by lots of bright green leaves and colorful blossoms
- Rounded leaves, similar to a water lily
- Brightly colored flowers with an open funnel shape and a long “tail” on the underside
- Flower colors of mahogany, orange, pink, red and yellow
- The Alaska series and Jewel of Africa feature variegated leaves
Dwarf nasturtiums are a great choice for edging. Semi-trailing nasturtiums will brighten your flower baskets and window boxes. You can easily cover a trellis with single-flower nasturtium climbers, which will send out runners up to 8 feet long.10 While the sizing will vary somewhat according to the type of nasturtium you choose and its growing conditions, you can expect the following:
- Bushy varieties: 12 inches tall by 18 inches wide
- Climbing nasturtiums: up to 10 feet tall
- Trailing nasturtiums: 3 to 4 feet long
The beauty of nasturtiums is found not only in their vibrant colors, but also the fact they will attract hummingbirds, as well as bees, butterflies and other beneficial pollinators to your yard and garden.
Tips on Growing Nasturtiums
In cooler climates, expect your nasturtiums to produce flowers from early summer through fall. In milder growing conditions, nasturtium plants will bloom fall through spring and fade in summer heat. Unless your plants have been stressed and are holding onto spent blooms, you generally do not need to deadhead nasturtiums. While nasturtiums are easy to grow, below are some tips to ensure your success in cultivating these eye-catching, edible plants:11,12
Since they are commonly started from seed, you may not find nasturtium plants at nurseries; however, seeds are readily available and germinate quickly (I recommend you try heirloom varieties)
Nasturtiums prefer lean soil so do not feed them; fertilizer will cause them to put out more foliage and fewer flowers
If you get frost, sow organic and heirloom seeds in spring and summer; direct seed outdoors as soon as the soil has warmed or start seeds indoors two to four weeks earlier. If you live in a warm-hot climate, you can plant nasturtiums anytime. Plant the seeds about one-half inch deep.
While they will bloom best in full sun, nasturtiums will grow in full sun to partial shade
Because they don’t like being transplanted, you should always use peat or paper pots to reduce transplant shock when moving plants outdoors
Nasturtiums do best with weekly watering; they can survive drought conditions, but will produce fewer flowers with less attractive foliage during dry spells
In terms of diseases and pests known to afflict nasturtiums, be on the lookout for aphids, as well as caterpillars, flea beetles and slugs. When planted alongside your vegetable garden, nasturtiums can act as a trap crop to draw pests, particularly aphids, away from other plants. Usually, a strong blast of water (or a spray of soapy water) is enough to knock out aphids. To avoid ingesting pests, always rinse the flowers well before eating them.
Design Ideas: Ways to Enjoy Nasturtium
Before choosing a nasturtium variety, give some thought to the design effect best suited to your yard or garden. You will want to pay attention to the varieties you choose because the flowers can sometimes be obstructed by the plant’s ambling foliage. If you are growing your nasturtiums at ground level, choose one of the newer varieties, such as the Alaska series, because they hold their flowers above their leaves, making them more easily seen. Some options for planting this cheerful flower include:13,14
- Bushy: These luxuriant ground-hugging nasturtiums, such as Alaska, Empress of India, Strawberries and Cream and Whirlybird, are great for edging, complementing similarly colored day lilies and roses
- Containers: Compact dwarf varieties like Alaska Variegated, Cherry Rose Jewel, Empress of India, Nasturtium Fiesta Blend and Peach Melba work well in containers
- Climbing varieties: Colorful nasturtium types such as Canarybird Creeper, Multicolor, Red Canary Creeper, Trailing Mix and White Moonlight will amble up walls or through shrubs
Ways to Use Incredible, Edible Nasturtiums
In the short video above, Nancy Baggett of KitchenLane.com presents three ideas on how to use nasturtiums, including adding them to salads, creating nasturtium vinegar and making nasturtium vinaigrette dressing. Using a variety of richly colored nasturtium blooms is the key to her simple recipes. Nasturtiums add a slightly peppery flavor that is similar to the taste of watercress. As always, I recommend you use organic ingredients to avoid unnecessary exposure to pesticides and other chemicals.
- 8 to 10 nasturtium blooms and leaves
- 4 to 5 blades of chives or garlic chives
- 2 blooms of chives or garlic chives (optional)
- 12 ounces (400 milliliters) unseasoned white rice vinegar or white wine vinegar
Place all the plant material into a glass bottle or jar and pour the vinegar over top. Secure the lid and store in a cool, dry place for three days before using. Use within six months.
Nasturtium Vinaigrette Dressing
Add all ingredients to mixing bowl and gently stir to combine. Pour dressing into a glass bottle or jar with a tight-fitting lid. Shake before use.
Although the flower is most often enjoyed, the entire nasturtium plant is edible. Their vibrant colors and tangy taste make nasturtiums a delicious addition to many dishes. When adding nasturtium flowers and leaves to salads, it is best to harvest them just prior to use. Besides using them in salads, the Micro Gardener suggests the following additional uses for nasturtiums:15
- Add leaves or blooms to sandwiches, wraps and vegetable juices
- Decorate cakes, other desserts and party trays with the flowers, or freeze them in ice cube trays to add a splash of color to cold beverages
- Incorporate chopped leaves and blooms into casseroles, soups, risottos and rice dishes; blend them into grass fed butter
- Stuff and bake the blooms as you would grape leaves, using a mixture of currants, nuts, rice and savory spices like cinnamon, cloves and mint
- Use chopped leaves to replace garlic or green onions in soups, stir-fries and other dishes
Beyond the mentioned uses, recipes abound for nasturtium pesto and pickled nasturtium seed pods, which some enjoy as a substitute for capers. Regardless of how you decide to use nasturtiums, these easy-to-grow edible flowers are sure to add a splash of color and health to your life.