Mizuna Mustard Seeds - (Brassica rapa)

Mizuna Mustard - The Emperor’s Asian Green

This spicy, bright, and gorgeous Japanese heirloom mustard green is a gardener's and cook’s dream. Once a famous green in the Japanese Emperor’s house, Mizuna grew in popularity and was widely cultivated before the mid-19th century. Even today, it is still highly favored.

Mizuna’s name comes from combining two Japanese words; “Mizu” for water and “nu” for mustard plant. The vegetable is included in the group of “fast-growing” vegetables. Because of the plant’s feathery appearance, Mizuna looks like a type of fern.

Often compared with arugula, Mizuna has a less “peppery” bite with more mustard flavors, yet not in an aggressive way. 

Details

Mizuna is a hearty annual Japanese mustard green in the Brassica family with distinctive feathery, dandelion-like toothed or serrated leaves and a mildly peppery, sweet, earthy flavor. An excellent "cut-and-come-again" variety that produces 8-15" tall, slender white stalks topped with rosettes of thick, deeply-cut dark green leaves.

This Japanese heirloom is slow to bolt, extending the season nicely for short and long-growing climates. It can be planted from early spring to late summer or early fall in mild winter areas.

Grow them all season as a baby green or leafy green, or they will be happy growing in containers or as part of an edible ornamental garden. Younger leaves are tender and milder, and the mature leaves are crisp with a peppery, piquant, and mildly bitter-sweet flavor. 

Many describe the flavor as a combination of arugula and mustard greens; Mizuna adds a deliciously subtle punch to salads, stir-fries, soups, and nabemono (Japanese hot pots). If arugula is too pungent, peppery, or spicy for you, then Mizuna will be just right.

If you don't know its name, it may seem familiar on your first taste, as it's commonly added to packaged spicy greens salad mixes.

Mizuna is also known as water greens, kyona, Japanese mustard greens, and spider mustard.

Interestingly, International Space Station crews are provided with fresh food from Mizuna mustard greens, demonstrating the feasibility of space agriculture. In specialized botany facilities, plants are grown under red-to-blue lighting and watered in pillows filled with growing medium.  

History

Plant historians believe Mizuna mustard is native to China and brought to Japan in the 8th century through trade or cultural exchange. It has been cultivated extensively in Japan since antiquity in the Kansai region in Kyoto. Historically, the vegetable was grown around the Mira-Dera temple. 

It is said that Japanese cultivation began in the Heian period (794 – 1185). Mizuna is special in Japanese culture and history and is used in many Japanese dishes.

Today, Mizuna is a “Kyo Yasai,” meaning it’s an heirloom vegetable from the Kyoto region, where the Royal family lived and acted as Japan’s national capital during the Edo period. Only 37 heirloom vegetable varieties that originated before 1868 and were grown under strict environmentally friendly practices in the Kyoto prefecture (district) were granted "Kyo Yasai" status in 1989.

Japanese traditional diets have been primarily plant-based for centuries. Because of its climate and location, Kyoto is ideally suited to growing vegetables, especially after becoming Japan's capital in 794. Many of the traditional vegetables in the region have been continuously cultivated for centuries, and their seeds are passed down from generation to generation. Traditional Japanese culture incorporates these vegetables into their customs and ceremonies. 

Mizuna greens grew in popularity in Europe and the United States during the late 20th century due to demands for exciting and nutritious ingredients and the popularity of Asian cuisine in Western countries. 

Uses

Mild, crispy, and crunchy, Mizuna goes well with any dish but is particularly good in salad. It is most commonly found in packaged spicy or gourmet salad mixes along with arugula, red oakleaf lettuce, green endive, red leaf lettuce, and other leafy greens across the globe.

Leading chefs love the unique texture and flavor, complementing different lettuce and other leafy vegetables. Mizuna is increasingly found on the menus of fine-dining restaurants worldwide.

Mizuna greens are an essential cultural ingredient in ozoni, a dish eaten during the Japanese New Year and consumed for good luck. Young green flowers are harvested when young and tender, enjoyed along with the greens and stems of the plant during the summer months, or removed from the stems and used on their own.

Mizuna pairs well with many ingredients, including citrus, Soy sauce, sesame, Miso, seafood, and several kinds of noodles. A traditional Japanese salad called "namasu" is made with thinly sliced vegetables and a vinegar-based dressing with chopped Mizuna leaves and stems. French cuisine uses Mizuna, known as “Japanese greens,” in warm and cold dishes. 

Sautéed Mizuna stems and leaves with onions or garlic make a flavorful side dish. Add the leaves and stems to stir-fries and as a last-minute topping to soups and stews. Substitute for basil or spinach in your favorite pesto recipe. 

Companion Planting

Because Mizuna is part of the Brassica family, it has many of the same concerns as other cruciferous vegetables. One notable exception seems to be cabbage moths, as Mizuna doesn’t seem to attract them. 

Beneficial companion plantings include celery, chamomile, corn, dill, garlic, mint, onions, rosemary, sage, thyme, and yarrow. Mizuna is said to improve celery flavors, while chamomile repels whiteflies and attracts beneficial insects. Dill attracts hoverflies, ladybugs, and lacewings to eat aphids and any cabbage worms that show up. Garlic is supposed to help improve the flavor of brassicas. Mint is a strong natural pest insect repellent, keeping cabbage loopers, flea beetles, whiteflies, and aphids at bay. Rosemary, sage, and thyme deter pest insects like cabbage moths and slugs from mustards. 

Plant Mizuna away from beans, members of the nightshade family (tomatoes, peppers, eggplant, etc.), and strawberries. 

Planting Tip

Mizuna greens are quick, easy-to-grow, cool-season plants that are slow to bolt and grow well in containers. They prefer well-drained soil rich in organic matter and grow best planted directly into the soil. Tolerant of light frosts yet very slow to bolt in the heat, Mizuna is an ideal vegetable for early spring or fall planting and excels with succession planting. 

It will even grow indoors in containers with moderate sun in cold winter areas. 

The ideal soil temperature is 55° to 75°F — seeds will germinate as low as 40°F but will take longer to sprout. A good test is to feel the soil with the palm of your hand first thing in the morning. If it feels cool but not unpleasantly cold, you can start early planting. When it doesn’t feel cool or warm, it is the ideal soil temperature, giving you the best germination. 

Mizuna loves at least six hours of sun but will tolerate partial shade. 

Japanese cultivation of Mizuna begins in mid-September, with a layer of fertilizer buried along the center of the row. The rows are raked into mounds — approximately 8” high and 4’ wide — and two drip irrigation T-tapes are laid lengthwise onto the rows. Four rows of Mizuna seed are sown on both sides of the tape; then the soil is watered. The seeds begin sprouting in three days, each showing pairs of lobes, with all seeds sprouting by the end of the first week. Stalks begin extending, and larger leaves appear in the third week.

Growing Tip

Mizuna grows much like other garden greens, tolerating nearly any soil but thriving in rich, loamy, moist soil but not overly damp. Add well-aged compost to the soil before planting.

Sow seeds directly in the garden 4-6” apart, lightly covering them with soil — no more than 1/8”. Thinning the weakest plants after about two to three weeks — ideally, you want the mature plants to be 10 to 12” apart. Remember, the tender, thinned leaves are much too delectable to throw away!

Keep the soil moist but not damp when the plants are small. An easy way to tell is that when you touch your fingertip to the soil, you should easily feel the soil moisture, but your fingertip shouldn’t be wet; only a slight sheen of moisture is perfect. 

A light layer of mulch helps keep the soil evenly moist.  

Harvest Tip

Mizuna is equally tasty when harvested as a micro-green, sprout, baby leaf, young green, or mature full-leaf and stem vegetable. The harvest method also accommodates your needs — cut the entire plant close to the ground for a single harvest or use the cut-and-come-again method by cutting the greens 2” above the ground for a longer, almost continual harvest. 

For the best quality and flavor, harvest in the morning after any dew has dried but before the day’s heat arrives, softening the greens. Younger leaves are more tender with a milder flavor, yet fully mature greens aren’t bitter or sharp like most European mustards or arugula.  

Learn More

• Growing Your Salad in a Container Garden
• Cool Season Vegetables to Love

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