Hydroponic Water Poppy: Growing Hydrocleys in Small Container Water Gardens
A hydroponic water poppy is Hydrocleys nymphoides grown in a tub of water instead of a garden bed. Its roots sit in a pot of heavy soil on the tub floor while its glossy leaves float on top.
The short answer
Water poppy is an emergent aquatic perennial with light yellow cup flowers. NC State Extension lists it for full sun in USDA Zones 9a to 11b. It grows in water up to 12 to 15 inches deep but prefers about 6 inches. Each flower lasts one day. Thin runners often.
What is water poppy?
NC State Extension describes water poppy as rooted in the pond bottom with leaves plus stems reaching out of the water. The leaves are thick, shiny, dark green plus heart shaped. Flowers are light yellow with a red and brown center. They rise above the water in summer.
Each plant spreads outward, not upward. NC State lists a height of 6 inches to 1 foot and a spread that can cover an area 5 feet across. As it spreads it makes plantlets that form their own roots. Dividing it means lifting those plantlets.
How deep should a water poppy tub be?
NC State notes water poppy survives in water up to 12 to 15 inches deep. It prefers shallow water near 6 inches, where its leaves float on the surface. Colorado State University Extension notes a pot 12 inches across and 10 inches deep suits most aquatic plants.
University of Illinois Extension advises matching each plant to its depth. A pot set on the floor of a deep container can drown a shallow water plant. Bricks, stones or upturned pots lift a plant to the right level.
| Factor | Target | Source |
|---|---|---|
| Water over the crown | About 6 inches, up to 12 to 15 | NC State |
| Pot size | 12 inches across, 10 inches deep | Colorado State |
| Soil | Heavy clay soil under 1 inch of gravel | Illinois |
| Light | Full sun, 6 or more hours | NC State |
| Bloom water | 70 degrees F or warmer | NC State |
Source: NC State Extension, Colorado State University Extension plus University of Illinois Extension.
How do you hold water poppy over winter?
NC State lists water poppy as hardy in Zones 9a to 11b. In places that are not tropical it advises bringing the plant indoors in a shallow tub. Hold the soil moist with good light until spring.
Clemson Cooperative Extension notes some pond plants die back or go dormant when freezing weather arrives. Trim dead growth before new shoots appear in spring.
How to: step by step
- Choose a solid tub at least 12 inches across.
- Pot the plant in heavy clay soil.
- Top the pot with up to 1 inch of gravel.
- Set the pot so about 6 inches of water covers the crown.
- Place the tub in full sun.
- Thin runners that cover more than half the surface.
Illinois Extension notes too much fertilizer in the water makes floating plants grow fast. Clemson advises against fertilizer, potting mix or compost in a wildlife pond because extra nutrients can cause algae blooms.
Troubleshooting
Few flowers: too little sun or cool water. Move the tub to full sun. NC State notes blooms start once water reaches 70 degrees F.
Leaves crowding the tub: fast runners. Lift out extra plantlets for compost.
Plant fades in fall: cold water. Bring it indoors in a shallow tub.
NC State notes water poppy is considered invasive in a few areas of Florida. Grow it only in a tub and never place plants or trimmings in natural ponds or streams.
For more on root media see hydroponic in different mediums. Read caring for your hydroponic system for system care. See aquarium water for cannabis plus pond water for cannabis for related water notes. Kind Seed Co also stocks cannabis seeds.
Sources
- Hydrocleys nymphoides (water poppy), NC State Extension Gardener Plant Toolbox
- Planting the water garden container, University of Illinois Extension
- Water gardens: planting aquatic plants (PlantTalk 1026), Colorado State University Extension
- Backyard wildlife ponds, Clemson Cooperative Extension, HGIC
FAQ
Is water poppy hardy outdoors?
NC State Extension lists water poppy as hardy in USDA Zones 9a to 11b. Outside those zones it advises bringing the plant indoors over winter in a shallow tub with moist soil plus good light.
How long does each water poppy flower last?
NC State Extension notes each bloom lasts only one day. The plant still blooms over a long season in summer, with new flowers opening above the leaves while the water is warm.
How fast does water poppy spread?
NC State lists a rapid growth rate. A single plant can cover an area about 5 feet across as its runners root new plantlets on the water surface. Thin it often in a small tub.
Does water poppy need fertilizer?
Clemson Cooperative Extension advises against fertilizer in a wildlife pond since extra nutrients can cause algae blooms. Illinois Extension notes floating plants grow fast when the water holds too much fertilizer.
How much water should cover water poppy?
NC State Extension notes water poppy survives in up to 12 to 15 inches of water. It prefers shallow water near 6 inches, where the leaves float flat on the surface.
