Nasturtium

January

about

Nasturtiums are in the plant family Tropaeolaceae and consist of approximately 80 species of annual and perennial herbaceous flowering plants in the genus Tropaeolum. Plants in this genus are native to the Andes Mountains in South and Central America but now grow all over the world. They tend to have showy, often intensely brightly colored flowers and rounded, pea-green peltate (shield-shaped) leaves with the petiole, or leafstalk, in the center of the leaf.

The species most commonly referred to as “nasturtium” is a hybrid of T. majus, T. minus, and T. peltophorum. Other names for nasturtium include garden nasturtium, Indian cress, Peruvian cress, and Mexican Cress.

The common name nasturtium and the use of the descriptor “cress” in many of its names refers to the mustard oil the plant produces which is similar to that produced by watercress (Nasturtium officinale, in the plant family Brassicaceae).

There are many varieties of nasturtium, and the plant can be compact or climbing in form. The funnel shaped flowers can be single or double and come in a range of colors including cream, yellow, orange and red, solid in color or striped and often with a dark blotch at the base of the petals. The large green leaves that are nearly circular range in size from 2 to 5 inches in diameter. Popular varieties of nasturtium are Jewel Mix, Empress of India, Alaska, and Black Velvet.

There are some cultivars that have variegated, almost speckled, leaves. Depending on the variety, the plant either forms a low mound or trails up to 3 feet.

Nasturtiums are most often grown as an ornamental, with their bright, attractive blooms and lilypad-like foliage, but it can also be grown as a vegetable since the flowers, leaves, and pods are all edible, with a spicy, peppery taste.

planting

Nasturtiums can form mounding bush forms or grow into vining trails and easily lend themselves to being grown in garden beds and borders or trained to climb up vertical supports. They are perfect for edging paths or adding to containers and hanging baskets.

These herbaceous flowers grow best in full sun with moist but well-drained soil. Nasturtiums prefer “poor” soil, low in organic matter and nutrients, so there is no need to add pre-plant fertilizer or amend the soil before planting.

Nasturtiums may be grown from seed or from transplants. If purchased at plant nurseries, they are often located alongside the herbs and vegetable starts. In North Central Florida, seeds can be planted from spring to fall. Seeds should be sown outside after the danger of frost passes, usually around mid-March.

Nasturtium seeds have a thick seeds coat, so for faster germination it is helpful to nick the seed or soak overnight in lukewarm water. Seeds should be sown about ½ to 1 inch deep and spaced 2 to 3 inches apart. If planting into a container, plant seeds directly into a pot with quality potting mix and good drainage.

Soil should be kept moist until germination, which should take 7 to 10 days. For bush varieties, thin seedlings 8 to 10 inches apart, and for trailing varieties 18 to 24 inches apart.

care

Nasturtiums are easy to care for since they are low maintenance. It is recommended to provide 1 inch of water per week to increase flowering and prevent the soil from drying out. These plants are moderately drought tolerant, but without watering they will have less flowers and look spindly.

Nasturtiums do not have a high nutrient demand, and usually do not require additional inputs to thrive. In fact, fertilizing these plants when not needed will lead to increased leaf growth and less flowering.

Pruning is an important part of nasturtium care, as it helps to promote growth and flowering. In trailing varieties, trim the longest stems by 6 to 12 inches and remove dead flowers or leaves by pinching them off at the base. For bushy varieties, trimming is not necessary, but pinching off dead flowers and leaves can stimulate growth and aid in the plant’s appearance. Another key factor in nasturtium care is providing support for growth. Climbing varieties will need trellising when they reach 7 inches tall. Dwarf forms do not require support and can be left freestanding.

Nasturtiums do not typically have pest problems. Leafminers often make serpentine trails on the leaves, but this doesn’t damage the plant. Aphids are a potential pest and can be a problem if crinkled foliage is observed, or plants appear unhealthy. Aphids can be controlled with insecticidal soaps. Root rot and bacterial leaf spot can also affect nasturtium under improper conditions. You can prevent these by providing good drainage, airflow between plants, and watering with drip irrigation.

Harvest



Nasturtiums are fast growing plants and should start producing flowers about 6 weeks after planting. The leaves and flowers can be harvested continuously throughout the growing season.

Flowers can be harvested as buds or in full bloom, and leaves will have their best flavor when they are young. As the plant gets older, the flavor of leaves and flowers will become spicier, so earlier harvesting is recommended for a mild taste. Flowers will wilt quickly, so it is recommended to harvest immediately before use.

Seed pods will develop about 4 months after seeding. Mature seed pods will be hardened and can be saved for future planting. Fallen seed pods should be collected, cleaned, and dried. Store in a paper envelope in a cool, dark spot for the next planting.

If flowers, leaves, or pods are to be harvested and consumed, avoid nonfood labeled pesticides on or near the plants.

digging a little deeper

Nasturtium is a wonderful companion plant for you garden, attracting pollinators, beneficial insects, and luring pests away from other garden vegetables. For example, Nasturtiums can be planted near vegetables acting as a ‘trap’ crop, that attracts aphids, various types of caterpillars, and other pests, deterring them from eating garden veggies. The aphids and other pests, in turn attract predatory insects, like wasps and hoverflies, which build up the population of beneficial insects in your garden ecosystem. Additionally, bees and butterflies are attracted to Nasturtiums, introducing more pollinators into your garden.

References

https://blogs.ifas.ufl.edu/escambiaco/2019/08/21/new-flavors-with-edible-flowers/

https://blogs.ifas.ufl.edu/osceolaco/2018/10/17/edible-flowers/

https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/nasturtium.html

Nasturtium, Garden – Tropaeolum majus L. https://edis.ifas.ufl.edu/publication/MV099

Badenes-Pérez, F.R., 2019. Trap crops and insectary plants in the order Brassicales. Annals of the Entomological Society of America, 112(4):318-329. DOI: 10.1093/aesa/say043

Companion Planting & Botanical Pesticides: Concepts & Resources. ATTRA Sustainable Agriculture. National Center for Appropriate Technology https://attradev.ncat.org/wp-content/uploads/2022/06/companion-planting.pdf


Authors

Dr. Colin Burrows, UF/IFAS Master Gardener Volunteer, Alachua County

Emily Deruelle, UF graduate student, Agroecology

Dr. Cynthia Nazario-Leary, UF/IFAS Environmental Horticulture Extension Agent, Alachua County

selecting, preparing, storing & cooking nasturtiums

Nasturtiums are a popular edible flower that is not only colorful but delicious. The trumpet-shaped blooms of nasturtium have a sweet, mildly spicy flavor, making a colorful garnish or addition to salads. All parts of the nasturtium plant are edible: flowers, leaves, stems, and young seed pods (mature seed pods have a very hard, unpleasant seed inside). All these parts have a distinct peppery flavor like radishes. That bite is strongest in the seeds and lightest in the flowers. The foliage is also edible and peppery tasting. The peppery flavor of the flower and leaves is outstanding, but you can also eat the tender stems and seed pods. Both the leaves and petals of the nasturtium plant are packed with nutrition, containing high levels of vitamin C, A, and D, beta-carotene, iron, manganese, and flavonoids. Nasturtiums are also a good source of micro elements such as potassium, phosphorus, calcium and magnesium, and macro elements, especially of zinc, copper, and iron.

 

Selecting/Harvesting:  You want to harvest at their peak of freshness when they are fully bloomed and are not wilting. Cut them in the cooler part of the day such as early morning or late evening after the dew has evaporated and midday heat sets in or after the high sun has gone down. They will have the highest water content and stay fresher longer. Use a clean pair of micro-tip pruning shears to cut the bloom just below the flower head.

 

Storage:  You should plan to use edible flowers within a day of harvesting them. Ideally, they should be cut just before use. You can also store unwashed in a basket or container with good air circulation for a day in the refrigerator. Wash them when you go to use them. To keep in refrigerator longer than a day. When you pick them clip a longer stem and place in a glass of water. Store in the refrigerator for 2 to 3 days making sure you change the water daily.It is not a good idea to store flowers and leaves together because the tender leaves will develop a very strong, hot flavor, unpleasant scent, and taste. So, it is best to store flowers and leaves in separate containers.

 

Preparing:  Wash nasturtiums only when you are ready to use them. To wash swirl the blooms in a bowl or cold water to wash and let them drip dry on a paper towel or clean dish towel. To use chop, them or use whole. The pods/seeds quick rinse in cool water, but once you’ve done that, use or begin pickling them immediately.

 

Cooking:  Nasturtiums pair well with the following:  garlic, chives, onions, pine nuts, Dijon, dill, parsley, tarragon, capers, lemons, beets, microgreens, spinach, potatoes, most soft cheeses, cottage cheese, parmesan cheese, chicken, and most fish. Nasturtium leaves are best suited for raw preparations and add a spicy or peppery flavor to dishes. They can be chopped and shredded into salads, used as the base for pesto, or chopped and combined with softened cheeses for spreads. Edible Flowers can be added to salads, pizza (sprinkle them fresh on top after cooking), ice cubes, lollipops, cupcakes, and more. Some edible flowers are better in sweet recipes and others may work better in savory dishes. Replace spinach: anywhere spinach is used, you can replace some (or all) of it with nasturtium leaves. This includes things like lasagna, minestrone, creamed spinach, quiche, quinoa or veggie patties, and spinach artichoke dip. Pesto: a unique pesto to use on pasta, bread, or swirl into some minestrone. You can also use half basil and half nasturtium leaves for a more classic flavor.

 

Flowers:  Salad:  use whole flowers or pull the petals apart. Add to the salad as a garnish instead of mixing them in with the dressing. Garnish: the flowers make pretty garnishes on appetizers, charcuterie boards, pasta, and pretty much anything you can think of. Stuff fresh blossoms with a blend of soft cheese (like goat, ricotta or cottage cheese) and fresh herbs, salmon, tuna or chicken salads or minced dried fruits. Mince the blossoms, add a little lemon peel and blend into fresh butter or make a hot tea. Use the zesty-tasting flower instead of mustard in sandwiches. Vinegar: a nasturtium-infused vinegar is peppery and works great in salad dressings or anything that benefits from a splash of vinegar. It's also a bright red-orange color that looks cute for gifts.

 

Leaves: can be stuffed with tuna or chicken salad, then rolled up as an entrée or snack. Use in risottos, soups, juices, casseroles, pesto, and rice dishes. Use the leaves to make a muffin liner for mini quiches by putting leaves in muffin tin, pouring batter over leaves then bake. Stuff and bake them as you would grape leaves. Try a mixture of rice, currants, nuts and savory spices like cinnamon, mint, and cloves.

 

Stems: use as garnish, add to pesto, fold into omelets, add to sandwiches or mustard and butters for herbal butter.

 

Seeds:  pickles to use in place of capers, dry, roast to use whole in place of peppercorns or crushed instead of pepper to season dishes and marinades.

stuffed nasturtium flowers

Ingredients: 

12 nasturtium petals (whole flowers)

1 (8 ounce) package cream cheese, softened

1 garlic clove, minced fine

1⁄2 tablespoon fresh chives (you may use chive blossoms, chopped)

1 tablespoon chopped fresh lemon verbena (or lemon balm, lemon thyme, lemon basil, lemon catnip, or lemon zest)


Directions:  

Make sure flowers are clean and dry. Pick as close to serving time as possible but use the same day. Store in the refrigerator until ready to use.

Mix cream cheese thoroughly with herbs. Season to taste. Place 1 or 2 teaspoons of mixture (depending on size of flower) in center of flower. Pull petals upwards to cover the cheese as much as possible. Press lightly into cheese to stick. This makes 4 servings, 4 stuffed flowers per person.

stuffed nasturtium leaves

Ingredients:

Filling

3 cups cooked short grain rice, (may substitute grains or other types of rice, or any combination)

1 Tablespoon extra-virgin olive oil

1 onion, finely chopped

1 clove garlic, finely chopped

1 cup chopped tomato, (fresh or canned/drained)

1/2-pound lean ground beef or lamb, (optional)

1/3 cup pine nuts, toasted

1/4 cup chopped fresh flat leaf parsley or mint

1/2 cup chopped nasturtium flowers

1-1/2 Tablespoons capers

1 T. extra virgin olive oil

1 teaspoon lemon juice

For preparation

20-25 fresh nasturtium leaves - stem trimmed close to the leaf

3/4 cup vegetable broth, or chicken broth

 

Directions:  

Preheat the oven to 350F. Wash the nasturtium leaves gently and set them aside. Making the filling:  Make the rice according to package directions and let it cool slightly before starting. Place the cooked rice in a large bowl - you’ll be adding the rest of the filling ingredients to the rice. Sauté the onions and garlic in the olive oil until softened but not browned, then add the chopped tomato and cook on medium heat for 3-5 minutes. Add this mixture to the rice and combine. Place the ground beef in the pan in which you cooked the onion/garlic/tomato mixture, and cook on medium heat, chopping as you go to get a fine crumbled burger. Once the burger is completely cooked, add it to the rice mixture, and combine. Now stir in the remaining ingredients - toasted pine nuts, chopped parsley, chopped nasturtium flowers, and capers. Taste, adjust with salt and pepper if needed. Making the stuffed nasturtium leaves

Place one of the nasturtium leaves on your work surface, stem side down. Put a teaspoon or more of the mixture in the center of the leaf, then carefully fold the two sides partially over the rice and roll tightly towards the top of the leaf, ending with the edge tucked underneath. Repeat with all the leaves and pack tightly in one layer with the seam of the leaf down (so they don’t unroll), into a glass or ceramic baking dish. Pour chicken broth over the stuffed nasturtium leaves. Cover the dish tightly and bake on the center rack of your oven for 45 minutes. Check to make sure the rolls are not drying out about halfway through cooking. If they are, spoon some hot broth over them. (Don't spoon cold broth into a hot glass or ceramic baking dish, as it can cause the pan to shatter!) Cool slightly and serve warm or wait longer and serve at room temperature. Before serving, drizzle with one tablespoon or so of olive oil, and a teaspoon or so of lemon juice. Refrigerate any remaining rolls. 

Preparing, Storing and Cooking Nasturtiums submitted by:  Martha Maddox, CEA IV, Family and Consumer Sciences Agent, UF/IFAS Extension Alachua County.