Secrets of Nuphar Pumila Revealed: A Comprehensive Guide

The Nuphar pumila is a perennial aquatic herbaceous plant of the Nymphaeaceae family. It has a rhizome about 2-3 centimeters in diameter.

The leaves are papery, broad ovate, or ovate, with a few being elliptical, measuring 6-17 centimeters in length and 6-12 centimeters in width. The flowers are about 3-4 centimeters in diameter.

The berry is ovate and approximately 3 centimeters long; the seeds are rectangular and 5 millimeters long, colored brown. The flowering season is from May to July, and the fruiting season from July to September.

It is found in China, Russia, Japan, and northern and central Europe, thriving in lakes and marshes.

The rhizome is edible and also used medicinally, known for its strengthening and blood-purifying effects; the flowers are cultivated for ornamental purposes.

I. Morphological Characteristics

This perennial aquatic herb has a rhizome diameter of 2-3 centimeters. Its leaves are papery, broadly ovate or ovate, occasionally elliptical, with lengths ranging from 6 to 17 centimeters and widths from 6 to 12 centimeters.

The leaf tips are rounded, the bases have a curved notch, heart-shaped, with the lobes widely separated and rounded.

The upper surfaces are glossy and hairless, while the undersides have dense soft hairs, with the lateral veins being pinnate and branching dichotomously several times; the leafstalks are 20-50 centimeters long and softly hairy.

The flowers are 3-4 centimeters in diameter, with hairy pedicels measuring 40-50 centimeters long. The sepals are yellow with a green center, rectangular or elliptical, and 1-2 centimeters long.

The petals are narrow wedge-shaped, 5-7 millimeters long, with a slightly indented tip. The stigma disc is often shallowly 10-lobed, pale yellow or with a hint of red.

The berries are ovate, about 3 centimeters long, with rectangular seeds 5 millimeters long, colored brown. The flowering period is from May to July, and the fruiting period is from July to September.

II. Habitat

Distributed in China, Russia, Japan, and the northern and central regions of Europe; it prefers wet, warm environments with sunlight and grows naturally in lakes and marshes.

It is not demanding regarding soil quality, with light loamy soil being most suitable. The Dwarf Waterlily is very cold-hardy.

III. Propagation Method

The Dwarf Waterlily mainly propagates asexually through the division of rhizomes. In the Jiangnan region of China, this is typically done from mid to late March when the climate is around 15°C, and the tender buds of the plant’s rhizome begin to sprout.

Cultivators can dig up the rhizomes, cut them into segments with 2-3 nodes each, and plant them in fields or ponds to propagate. Generally, a single plant will cover a water surface area of 10-20 square meters.

Once planted, a certain water level should be maintained so that the plants neither dry out nor are overwhelmed by floods, allowing them to propagate naturally without the need for annual replanting.

IV. Cultivation Techniques

Pot Planting of Dwarf Waterlily

The Dwarf Waterlily, Nuphar pumila, is best suited for pot cultivation, ideally undertaken in late March or early April. For containers, Yixing glazed or porcelain pottery pots are recommended, and it’s important to prepare the potting soil in advance.

Gardeners can dig up the nutrient-rich silt from ponds or fields in the spring and fall, allowing it to fully air-dry and sun-cure.

The following year, this thoroughly dried soil should be crushed finely, mixed with base fertilizer and well-rotted manure, and then piled up until around the Qingming festival, when the temperature rises to 15-20°C.

At this point, the soil should be finely sifted and the finer soil collected for use.

When potting, cut the rhizomes of the Dwarf Waterlily with a sharp knife, ensuring each segment has at least two nodes and young buds.

Handle with care to avoid damaging the bud tips. Place a layer of fine sand at the bottom of the new pot, which facilitates the removal of the plant for propagation in the following year.

Fill the pot with the prepared soil, water it until a thin mud forms, then bury the rhizomes in the soil. Initially, water sparingly to ensure the soil and rhizomes are in close contact, and then water until there is 1-2 cm of water above the soil surface.

Finally, place the pot on a sunny windowsill and undertake normal care and maintenance. With proper management, by late April or early May, flower stalks will break through the water, buds will stand erect, and soon the flowers will blossom in abundance.

Water and Fertilizer Management

Watering: The Dwarf Waterlily naturally thrives in fertile lakes and marshes, thus preferring moist conditions and not tolerating drought. However, it is sensitive to being submerged too deeply.

When watering, it is crucial to adjust the temperature of the tap water to match the ambient temperature before irrigation. For newly planted specimens, watering until just visible on the soil surface is sufficient.

This limited watering helps the soil absorb heat, raising its temperature and encouraging the sprouting of new shoots. If the initial water level is too deep, the soil temperature remains low, leading to slow bud development.

As the leaves and floating leaves start to grow, the water level should be gradually increased after 2-3 days. Regular watering adjustments should be made every 2-3 days based on actual water consumption.

During the hot summer months, when evaporation is high and temperatures soar, plants on balconies will require more frequent watering, possibly twice daily, to prevent wilting, yellowing leaves, and bud drop.

If such symptoms occur, immediate watering is necessary to rescue the plant, allowing it to continue growing, re-leafing, and flowering.

It is not advisable to cultivate the Dwarf Waterlily in deep tubs of water, as excessive depth and water volume can severely hinder plant growth.

Excess water can lower both water and soil temperatures, prevent rhizomes from anchoring properly, and may cause them to drift and rot.

Even during the growth period, the water level should not exceed the leaves. During rainy periods, excess water should be poured out to prevent the risk of drowning the plant.

In winter, when the Dwarf Waterlily enters a dormant phase, the soil should be kept moist to prevent cracking and rust disease on the rhizomes, which could affect growth and development in the following year.

Fertilizing: The Dwarf Waterlily is fond of rich soil, so ensure that the soil has sufficient fertility when planting new specimens. During growth and development, nutrients must be replenished timely.

During the vegetative growth phase, granular solid fertilizers made from oil cake, bone meal, and manure mixed with a small amount of ditch mud can be applied every ten to fifteen days at a rate of 50-100 grams per pot.

The Dwarf Waterlily prefers solid fertilizers and it is best to apply them in the center of the pot, as the rhizomes tend to grow along the pot’s edge, where the roots are located. Applying fertilizer in the center prevents fermentation and root damage.

If applying liquid fertilizer, take care to avoid contact with the leaves and buds to prevent rot. If leaves appear thin and pale, quick-acting fertilizers such as urea or potassium dihydrogen phosphate can be applied at 10-25 grams per pot, once a week for 3-4 consecutive weeks to revitalize the plant.

If the plant’s growth is too vigorous, with dark green, bluish leaves that are too thick, and flower buds are not differentiating, it may be helpful to apply potassium dihydrogen phosphate 2-3 times to meet the plant’s reproductive growth nutrient requirements.

However, gardeners should take special care not to over-fertilize, whether it’s the base fertilizer or additional applications. Over-fertilizing can inhibit bud development or, in severe cases, cause rhizome rot and cultivation failure.

Excessive fertilization can result in waterlogged, foul-smelling, greenish-black water, scorched leaves, or buds that wither and die.

In such cases, immediate action should be taken to dilute the concentration by changing the water 2-3 times, ensuring the plant’s normal growth.

Temperature and Light Exposure

Temperature: The water poppy thrives in warm conditions with plenty of sunlight. When cultivated as houseplants, they often suffer from insufficient sunlight, which affects their ability to form flower buds and bloom.

Therefore, for potted cultivation, it’s crucial to place them in a sunny spot where they can receive direct sunlight. This ensures vigorous plant growth. The water poppy, being an aquatic plant, relies heavily on sunlight.

Its rhizomes are buried in the underwater soil, and it can only absorb sunlight through its leaves, which is essential for the plant’s physiological and biochemical development.

The plant needs to harness light energy to carry out photosynthesis effectively, creating the nutrients necessary for the growth and development of its rhizomes and overall structure.

Cultivators should cater to its growth habits by meeting its light requirements. During the peak growth season in summer, it’s best to place the potted plant on an east-facing balcony in the morning and a west-facing balcony in the afternoon to bask in the full day’s sun.

With this care, the water poppy will surely flourish, blooming profusely and growing vigorously.

Light Exposure: Sunlight is vital for the growth of the water poppy, as it promotes the formation of flower buds. In similar conditions, plants that receive ample sunlight have lush leaves and abundant blooms.

In contrast, those lacking in light have dull leaves with less vibrant green color, and insufficient nutrients to support budding and flowering. With temperatures between 15-35°C, the water poppy’s photosynthesis is exceptionally active.

If the plant receives over 12 hours of sunlight at an intensity of 45,000 to 60,000 lux daily, it will continuously produce fresh flowers.

Light exposure is the energy source for the plant to create nutritional substances, and without it, photosynthesis cannot occur, severely affecting plant growth.

This is why some water poppies grown indoors may have weak, spindly leaves and fail to flower, primarily due to inadequate light exposure.

V. Primary Value

Medicinal Use

The rhizomes of the water poppy are edible and have medicinal properties, known for their strengthening and blood-purifying effects; the whole plant, seeds, and rhizomes are used in herbal medicine.

The entire plant: nourishes yin and clears heat. Seeds and rhizomes: strengthen the spleen and stomach, promote blood circulation, and regulate menstruation.

The whole plant is used for labor-induced debility, yin deficiency with fever, and night sweats; it is also applied topically for cuts. Seeds are used for spleen deficiency with poor appetite and irregular menstruation.

Rhizomes are used for indigestion due to spleen deficiency, yin deficiency with cough and night sweats, menstrual irregularities and dysmenorrhea due to blood stasis, and injuries from falls and blows.

Ornamental

The water poppy is a perennial aquatic herb with a rhizomatous root system. Its floating leaves are horseshoe-shaped, glossy green on the surface, and purplish-red on the underside with a dense covering of soft hairs, making it quite beautiful.

It is an ornamental plant valued for both its foliage and flowers; it blooms in the summer with bright golden-yellow flowers.