Water poppy

Hydrocleys nymphoides

Also known as Water-poppy, Yellow water poppy

FreshwaterFloatingRunnersPlantlets

Invasive. Water poppy is invasive and regulated in parts of Australia and elsewhere. Never release into the wild; dispose of in the trash.

Water poppy (Hydrocleys nymphoides) — no rights reserved · cc0

Care at a glance

Light: High light
CO2: No CO₂ needed
Temperature: 64–82°F; 18–28°C
Max height: 11.8 in; 30 cm

Growth rate: Fast
Placement: Floating
Type: Floating
pH: 6.0–7.5
Hardness: 3–15 dGH
Spread: 39.4 in (100 cm)
Nutrient uptake: Root + water column
Growth region: Emersed
Difficulty: Easy
Family: Alismataceae
Origin: Central and South America

Overview

Water poppy is a marginal and floating pond plant more than a submersed aquarium plant. It is easy and fast-growing, and it is an invasive weed in several regions.

Did you know

Each yellow water poppy flower opens for a single day before fading. An established mat produces a steady succession of one-day blooms through the warm season.

Caring for water poppy

Root water poppy in a rich substrate under shallow water, and it sends waxy leaves and yellow flowers up to the surface. It can also float as a loose mat.

Give it bright, high light, though it needs no added CO2. It feeds through both roots and leaves, so use root tabs near its roots along with a liquid fertilizer. Keep the water at 64 to 82°F (18 to 28°C).

It grows fast. New plants form along its runners and break away, and small plantlets can be detached once they have a few roots.

Water poppy is invasive. It is a declared or regionally regulated weed across Australia, in Queensland, New South Wales and Victoria. Several western US states ban its import, though it is not on the US federal noxious weed list. Never release it into natural waterways, and put trimmings in the trash, since it regrows readily from fragments.

Good to know

Water poppy, Hydrocleys nymphoides, sits in the water-plantain family Alismataceae. It is not one of the true water lilies its rounded floating leaves resemble. It reproduces largely by fragmentation and runners rather than seed, which is a big part of why it spreads so aggressively once loose. It is also sold as yellow water poppy.

In the wild

Water poppy is native to still and slow-moving fresh water in Central and South America. It roots in shallow mud and floats its foliage on the surface, forming dense mats topped with three-petaled yellow flowers.

Common questions

Does water poppy need to be planted in the substrate?

No. Water poppy can root in the substrate or float as a loose mat.

Does water poppy need CO2?

No. Water poppy grows well without added CO2.

How much light does water poppy need?

Water poppy needs high light from a strong planted-tank LED.

Does water poppy need root tabs?

They help. Water poppy takes nutrients through both its roots and its leaves. Root tabs near its roots and a liquid fertilizer cover both.

How do you propagate water poppy?

Water poppy propagates by runners and plantlets. New plants form along its runners and break away to float on their own. Plantlets bud from the parent and drift off.