The Ultimate Guide to Growing Okinawa Spinach

I. Introduction to Okinawa Spinach: Identification and Characteristics

1. Botanical and Common Names

The plant is most correctly identified by its botanical names, Gynura crepioides or its synonym, Gynura bicolor. It belongs to the Asteraceae family (キク科 in Japanese), which also includes daisies and sunflowers. It is closely related to another edible plant known as Longevity Spinach (Gynura procumbens).

Across the world, it has accumulated a remarkable number of common names, a testament to its widespread cultivation. These include Okinawa spinach, cholesterol spinach, dawn dewa, leaves of the gods, Mollucan spinach, handama, gynura, hung-tsoi (or hong tsoi), purple spinach, red vegetable, Okinawa lettuce, Velvet Plant, Kinjiso (金時草), Redflower Ragleaf, and Fireweed. In Japan, it is also called Suizenjina (スイゼンジナ or 水前寺菜) and Handama (ハンダマ), with additional regional names like Shikibuso (式部草), Date-murasaki (伊達むらさき), Fuji-misou (ふじ美草), Sumire-ba (すみれ葉), Nori-na (のり菜), and Garasha-na (ガラシャ菜).

2. Origin and Native Habitat

Okinawa spinach is native to a broad swath of tropical Asia, including Indonesia and Japan. Its natural range extends through Northeastern India, Nepal, Myanmar, southern China, and Taiwan. In these regions, it demonstrates its preference for specific environments; for example, in Singapore, it is found growing wild along forest streams and on sandy slopes, indicating a need for both moisture and good drainage.

3. Plant Characteristics

#### a. Growth Habit

This plant is a dense, low-growing perennial with a bushy, sprawling form, typically reaching a height of 40-70 cm (up to about 4 feet). It features a shallow root system, which makes it an excellent candidate for container gardening. Be aware that it is a fast spreader. Its stems have the ability to root wherever they touch the soil, a characteristic that allows it to form a thick, edible ground cover but also means it can become invasive if left unmanaged.

#### b. Leaf Appearance

The most striking feature is its two-toned leaves: the top surface is a shiny green, while the underside is a rich, deep purple. This vibrant purple coloration comes from anthocyanin, a type of antioxidant polyphenol. The intensity of this purple becomes more vivid when there is a large temperature difference between day and night. It is important to note that this beautiful color is lost when the leaves are cooked. A fully green variety also exists, and observation suggests the purple variety may thrive better in deeper shade.

c. Flowers and Seeds

From late summer into winter, the plant produces small, orange flowers that resemble cotton tufts and are effective at attracting butterflies. However, the plant flowers infrequently, and the seeds contained in the flower tips are rarely viable. This difficulty in collecting reliable seed is the primary reason propagation is almost always done via stem cuttings. For the home gardener, it is a common and effective practice to remove the flowers as they appear. This isn’t just for tidiness; it directs the plant’s finite energy away from seed production and channels it back into creating more of the desirable, edible leaves. As one gardener noted, “Around Christmas time my Okinawa spinach blooms. I usually just cut them off to keep the strength of the plant going to the leaves.”

## II. Cultivation Guide: How to Grow Okinawa Spinach

1. Ideal Climate and Temperature

As a tropical native, Okinawa spinach thrives in warm, wet conditions, making it perfectly suited for subtropical and tropical climates. It is sensitive to frost, which can kill the foliage. However, it is surprisingly hardy and can survive frosts down to -3°C if it is grown in a protected location. One grower shared that “growing it next to a brick wall of the house with morning sun has allowed it to survive what has been for us a fairly hard winter.” Even if the top growth dies back, the plant may re-sprout from its base when the weather warms. In colder climates, it can be treated as a perennial grown as an annual. To extend the harvest season, a clear vinyl tunnel can provide the necessary frost protection and insulation. Growth will stall when daytime temperatures consistently fall below 15°C.

2. Sunlight Requirements

The plant is adaptable, growing well in conditions ranging from full sun to partial shade. To thrive, it requires at least some direct sun. A personal account illustrates this point: “I accidentally planted a cutting in a position that became obscured by taller leafy greens and it didn’t grow at all in winter.” In very hot climates, however, it may perform better with some protection from intense afternoon sun. Providing partial shade or 4-8 hours of indirect sunlight can prevent sunburn, which may occur with more than 4 hours of direct, harsh sun.

3. Soil Preparation and pH

The ideal growing medium is a rich, fertile, and well-drained soil with a slightly acidic to neutral pH of 6.0-6.5. The most critical factor is drainage, as the plant’s roots will rot if they sit in waterlogged soil—a condition known as root hypoxia, where the roots are deprived of oxygen.

For planting in the ground, prepare the bed two weeks in advance by tilling in 100g/m² of dolomite lime. One week before planting, amend the soil with 2kg/m² of compost and 100g/m² of chemical fertilizer. For container growing, you can use a high-quality commercial potting mix or create your own blend. A proven recipe is:

• Akadama soil (7 parts)
• Leaf mold (2 parts)
• Vermiculite (1 part)

To this mix, add 10-20g of lime and 10-20g of fertilizer per 10 liters of soil.

4. Watering Needs

This plant requires ample and consistent water to produce lush growth. It is not very drought tolerant; during dry periods, it will stop producing new leaves, though it will not necessarily die. Maintaining a layer of mulch around the plant is an excellent strategy for retaining soil moisture and reducing watering frequency. As a general guide, provide 1.5-2 liters of water per plant. For a low-tech, highly effective irrigation solution, one gardener uses “an olla made from two small terra cotta pots in the centre to allow easy watering and to keep the plant moist in hot dry weather.”

5. Spacing and Garden Layout

Provide adequate space for plants to spread by spacing them 30-60 cm apart. If planting in rows, allow 50 cm or more between each row to ensure good air circulation and light penetration. For raised beds, a bed width of 50 cm can accommodate a single row, while a 70-80 cm width is suitable for two rows. A bed height of 10-15 cm is sufficient. To prevent the buildup of soil-borne pests and diseases, it is good practice to implement a 1-2 year crop rotation, meaning you avoid planting it in the same spot year after year.

6. Container and Indoor Growing

Its shallow root system makes Okinawa spinach exceptionally well-suited for growing in containers. It can be cultivated in pots (at least 10cm deep), hanging baskets, or larger tubs. For sizing, a medium 60cm planter can comfortably house one or two plants, while a single plant will do well in a deep pot of No. 10 size or larger. It can also be grown successfully indoors on a windowsill that receives good light.

## III. Propagation: Creating New Plants from Cuttings

1. Primary Method: Stem Cuttings

Propagation is best and most reliably achieved through stem cuttings. This is the preferred method because the plant flowers infrequently and rarely produces viable seed, making seed propagation impractical. You can take cuttings from a healthy, growing plant in your garden or even start a new plant from stems purchased at an Asian market.

2. Preparing the Cuttings

Select healthy stems and take tip cuttings that are 10-20 cm (150-200mm) long and have 5-6 leaves. Make a clean cut at an angle just below a leaf node—the small bump on the stem where a leaf emerges. Then, carefully remove the leaves from the lower half of the cutting, as this is the portion that will be submerged in water or soil.

3. Rooting Process

a. Rooting in Water

Placing cuttings in water first can improve results. Use a glass of plain tap water, avoiding mineral water. If the water becomes cloudy, change it daily to prevent bacterial growth. Roots should begin to form within 7-10 days. It is crucial to plant the rooted cuttings within 3 days of seeing new roots; if left in water too long, they can lose vigor and become more susceptible to rot upon being transferred to soil.

b. Planting Directly in Soil

Cuttings can also be planted directly into moist soil. The plant roots so readily that no rooting stimulant or hormone is necessary for new roots to form rapidly. This is a testament to the plant’s vigorous and adaptable nature.

### 4. Optimal Timing for Propagation

For the highest success rate, take cuttings during periods of active growth. This is typically in the spring (April-June) or autumn (September-October). The ideal environmental conditions are a soil temperature of at least 25°C and an ambient air temperature between 20-25°C.

IV. Plant Care and Maintenance

1. Fertilizing

Okinawa spinach is not a heavy feeder and has modest nutrient requirements. An occasional liquid feed applied at the start of the warmer growing seasons is often all that is needed. To encourage a flush of new growth after a heavy harvest, you can apply a high-nitrogen fertilizer once a month. For container-grown plants, use 5-10g per plant. For in-ground plants, apply 20-30g/m². Begin this top-dressing about two weeks after planting your seedlings or once the plant has reached a height of 20cm. A clear visual cue of nutrient deficiency is a fading of the leaves’ vibrant color.

2. Pruning for Health and Vigor

The plant responds exceptionally well to pruning. Regular trimming encourages a dense, bushy habit and can prolong the life of the plant by stimulating new growth. To manage its tendency to spread aggressively, it is more effective to prune entire branches rather than simply harvesting individual leaves. As one gardener advises, “After it took over one of my raised planters, I like to keep it into shape by pruning branches instead of merely harvesting leaves.”

### 3. Pest and Disease Management

a. Common Pests

While relatively pest-free, the plant can be affected by a few common garden inhabitants. Slugs are a significant pest and are highly attracted to the tender leaves. One grower offers a practical solution: “The slugs love it. This is why I grow mine in a large tub up off the ground. It is easy then for me to check for slugs on my weekly hunts in the garden with my flashlight before I go to bed.” Other potential pests include leaf miners, which tunnel inside the leaves; aphids; grasshoppers; armyworms; mealybugs; and spider mites. If you see signs of leaf miners, prune and discard the affected leaves immediately to prevent their spread. Aphids can often be kept in check by encouraging beneficial insects like ladybirds to populate your garden.

#### b. Potential Diseases

The primary disease threats are fungal or bacterial in nature, including Anthracnose, bacterial wilt, virus diseases, and various mold diseases. Prevention is the best strategy. These issues thrive in damp, stagnant conditions, so ensuring good air circulation, providing proper sun exposure, and planting in well-drained soil are your key defenses against them.

4. General Maintenance Tasks

Applying a layer of mulch around the base of the plant is highly recommended. This serves two purposes: it helps the soil retain moisture, reducing your watering duties, and it suppresses the growth of competing weeds. A dense, well-pruned plant will also help shade out weeds. If heavy rain or watering exposes the shallow roots, perform a task known as “earthing up” by simply hilling up soil around the base of the plant to cover them.

V. Harvesting and Culinary Use

1. When and How to Harvest

You can begin harvesting about two months after planting, once the plant is established and has reached a height of over 30 cm. Employ the “cut-and-come-again” method, which allows for a continuous harvest. Snip the tender top 15-20 cm of the young leaves and shoots. This can be done every two weeks throughout the growing season, which typically runs from summer through autumn (June to November). Harvesting the main stem in this way actually encourages the plant to produce more side shoots, resulting in a bushier, more productive plant.

It is best to stop harvesting after October; this allows the plant to build up and store energy reserves to survive the winter.

### 2. Flavor Profile and Texture

The leaves possess a crisp, nutty taste with a subtle hint of pine. When cooked, they undergo a textural transformation, developing a unique slimy, mucilaginous quality that is often compared to wakame seaweed. To avoid this texture, do not overcook the leaves. The key is to add them at the very end of the cooking process for just a few minutes.

3. Culinary Applications

a. Raw Preparations

The young leaves and tender tips have the best flavor and texture for raw consumption. They are excellent when sliced thinly at an angle and added to salads, where they provide a satisfying crunch.

b. Cooked Dishes

Older leaves are best cooked. The plant is incredibly versatile and can be incorporated into stir-fries, tempura, stews, soups (including miso soup), curries, and omelettes. They can also be steamed along with rice if you add them for the last 7 minutes of the cooking time. For a visually appealing and flavorful dish, one cook suggests pairing it with yellow sweet peppers in a stir-fry “to make a really pretty stir-fry and to sweeten things up.”

c. Beverages

The leaves can be added to green juices or smoothies, but be aware that a little goes a long way, as it can make the drink foamy. The stems and roots can also be used to make a tea.

4. Storage and Selection Tips

When purchasing from a market, choose plants that have deep purple undersides and a large number of leaves, which indicates vigor. For longer storage, it is better to harvest a small branch rather than individual leaves. To preserve freshness, wrap the branch in a damp paper towel, place it in a plastic bag, and store it upright in your refrigerator’s crisper drawer.

5. Nutritional and Medicinal Profile

Its common name, “cholesterol spinach,” hints at claims that it can help lower cholesterol, and it is regarded as both a vegetable and a medicinal herb in many cultures. It is a nutritious green-yellow vegetable, high in protein and a good source of vitamins like beta-carotene (a precursor to Vitamin A) and Vitamin C, as well as minerals like iron. The signature purple pigment is due to anthocyanin, a potent antioxidant polyphenol.

VI. Edible Landscaping and Gardener Experiences

1. Ornamental and Practical Uses in the Garden

Beyond its culinary value, Okinawa spinach is an attractive ornamental shrub that adds vibrant color to an edible landscape. Its sprawling habit makes it an excellent choice for an edible ground cover or a border plant. It can be grown as an underplanting beneath taller vegetables like kale and eggplant or used to create a living mulch around the base of fruit trees.

### 2. A Gardener’s Philosophy: “Free Food” and Low Maintenance

This plant is the embodiment of a low-effort, high-reward crop. As one gardener explains their philosophy, “Growing a regular western style vegetable garden is not really my thing… I am a lazy gardener who does not want to spend a lot of time and effort with fussy plants. I like the idea of growing free food.” Okinawa spinach perfectly fits this ethos, as once it is established, it requires almost no care to provide a steady supply of greens.

3. Personal Stories and Propagation Success

The ease with which this plant can be shared and grown is a common theme among gardeners. One person shared, “About a year ago, a Chinese friend of ours gave me some Okinawa spinach (hung tsoi or hong tsoi in Chinese), which I have been able to propagate, and it goes really well in any of the leafy vegetable recipes…”

Another grower’s experience highlights its resilience and productivity: “Okinawan spinach is one of the first plants I started growing… I just stuck it into the ground in cinder, and forgot about it. Nearly two years later, it’s still thriving and is a keystone ornamental… Making it extremely easy to grab a running ‘vine’ and cut it off to eat the leaves. This, in-turn, gives me propagation materials, I then take them and stick them into the ground in the food forest. Generating an overabundance of high quality leafy greens for consumption. Wow, I love tropical gardening!”

VII. FAQs

Can I eat Okinawa spinach raw?Yes, you can. The young leaves and tender tips are best for eating raw. They have a pleasant crisp, nutty flavor and are excellent when thinly sliced and added to salads for extra crunch and color. Why does my cooked Okinawa spinach get slimy, and how can I prevent it?The leaves contain natural compounds that create a mucilaginous, or slimy, texture when cooked, which is very similar to that of wakame seaweed. This is a normal characteristic of the plant. To prevent or minimize this, the key is to avoid overcooking. Add the leaves to your dish at the very end of the cooking process and cook them for only a few minutes until they are just wilted. Can I grow Okinawa spinach in a cold climate with frost?Yes, it is possible with some protection. While the plant is frost-sensitive, it can survive temperatures as low as -3°C if it is planted in a sheltered location, such as against the warm brick wall of a house. Even if frost kills the leaves and stems, the root system may survive and re-sprout in the spring. For gardeners in colder zones, using a clear vinyl tunnel can protect the plant over winter, or you can simply grow it as an annual. How do I create new plants? Should I use seeds?You should not use seeds. The plant rarely produces viable seeds, so the best and easiest method of propagation is from stem cuttings. To do this, take 10-20 cm cuttings from the tips of healthy stems, remove the lower leaves, and either place them in a glass of water to root or plant them directly into moist soil. They root so readily that no rooting hormone is needed. Is Okinawa spinach invasive?It has the potential to be invasive. It is a fast-spreading plant because its stems can develop roots wherever they make contact with the soil. This allows it to form a dense ground cover and spread quickly. To keep it under control, it is recommended to prune entire branches regularly as part of your harvesting, rather than just picking individual leaves. Should I remove the flowers?Yes, it is generally recommended to cut off the small, orange flowers when they appear. The horticultural reason for this is to redirect the plant’s energy. By removing the flowers, you prevent the plant from spending energy on producing seeds (which are rarely viable anyway) and encourage it to focus on what you want: producing more lush, edible leaves.