Pygmy water lily

Pygmy water lily key facts

Growing Difficulty

Intermediate

Lifespan

Perennial

Size

Leaves 8–19 cm long; flowers 3–7 cm across

Watering

A little slow-release fertiliser in the growing season

Lighting

Like other hardy water lilies, give at least half a day, ideally a full day, of direct sun.

CO2 & Fertilizer

It grows naturally in nutrient-poor water, so feed sparingly with slow-release tablets pushed into the soil.

Water Temperature & Quality

Cold-hardy; overwinter outdoors in standing water without letting the rhizome freeze. Natural habitats are neutral to slightly acidic.

Substrate & Attachment

Plant in paddy or arakida soil with about 10 cm of water over the crown.

Trimming & Propagation

It does not multiply by rhizome; propagate from seed.

Cautions

Red-listed in many prefectures: buy cultivated plants and never collect wild ones, and check the scientific name to avoid hybrids. Carp and crayfish eat it. Do not plant or dump it in natural waters.

About Pygmy water lily

Pygmy water lily, Japan's only native water lily, features 3-7cm white blooms and reddish-purple leaf undersides. This perennial aquatic suits growers with some experience and pairs well with a Japanese-style water garden.

7 things to know before growing Pygmy water lily

1. 1Choose a sunny spot

   Pygmy water lily flowers best in a bright, sunny outdoor location. Aim for at least half a day of direct sun to encourage steady blooming.

2. 2Keep the water shallow

   With leaves around 8 to 19cm long, this plant grows well in a shallow water basin or lily bowl. Choose a depth where the leaves can reach the surface comfortably, rather than a deep container.

3. 3Use heavy aquatic soil

   A heavy aquatic-plant soil, such as paddy soil, helps anchor the roots and keeps the plant from shifting in the water. Lightweight potting mixes tend to break apart underwater and aren't suitable.

4. 4Repot during the growing season

   Once the plant outgrows its pot, repot it during the active growing season. Roots that become too crowded can reduce flowering, so repotting roughly every few years, as needed, works well.

5. 5Can overwinter outdoors

   As a perennial, it can survive winter outdoors with some cold protection. In areas where the water surface freezes, sinking the container to a depth that stays unfrozen helps it get through the season.

6. 6Fertilize sparingly

   Too much fertilizer can push leaf growth at the expense of flowers. A small amount of slow-release fertilizer during the growing season is usually enough to keep growth balanced.

7. 7Choose nursery-grown plants and check the name

   Look for a plant with minimal leaf damage or discoloration and firm, healthy roots — this makes for more reliable growth afterward. Because pygmy water lily is listed as endangered or threatened in many prefectures, choose nursery-grown stock rather than plants collected from the wild. Check the scientific name (Nymphaea tetragona) as well, so you don't mistake a hybrid water lily for it. Never plant or dump it in ponds, rivers or waterways, and dry out unwanted plants before disposing of them with household waste.

Frequently asked questions about Pygmy water lily

Q.Can beginners grow pygmy water lily?

A.It's considered an intermediate-level plant. It's manageable if you understand the basics of aquatic plants — water depth, sunlight, and soil — but it suits growers with some prior plant-care experience more than absolute beginners.

Q.When does it bloom, and how large are the flowers?

A.The flowers are about 3 to 7cm across and open on the water's surface during the growing season. They're said to open around 2pm, a habit linked to the origin of the plant's Japanese name.

Q.Can it be grown in a small container like a lily bowl?

A.With leaves around 8 to 19cm long, it stays compact enough to grow well in a relatively small container, such as a lily bowl. You don't need a deep pond to enjoy it.

Q.Is the reddish-purple leaf underside a sign of disease?

A.No, the reddish-purple color is a natural trait of the plant, not a sign of disease. The contrast between the leaf's top and underside colors is actually part of its appeal.

Q.Is it fine to leave it outdoors through winter?

A.As a perennial, it can overwinter outdoors with some cold protection. Depending on your climate, sinking the container to a depth where the water won't freeze is a helpful approach.

Handy Growing Tools for Pygmy water lily

Learn more about Pygmy water lily in the encyclopedia

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