Hydroponic Iris in Water: Bog Iris in Containers
Hydroponic iris in water works with iris species that grow in wetlands. NC State Extension says northern blue flag can grow in up to 4 inches of standing fresh water.
The short answer
Hydroponic iris in water suits native blue flag iris. NC State says northern blue flag grows in up to 4 inches of standing water. Southern blue flag grows even in 6 inches plus can stay in water over winter. Colorado State suggests a pot 12 inches across plus ten inches deep for most aquatics.
Which iris grow in standing water?
NC State says the common name flag comes from an old English word for reeds. It refers to the plant’s liking for wetlands. Northern blue flag prefers rich moist soil plus full sun, though it takes partial shade. Southern blue flag grows in moist to very wet soil in full sun. It should not dry out during the growing season.
| Option | What it does | Source |
|---|---|---|
| Northern blue flag | Up to 4 inches | Iris versicolor (northern blue flag) |
| Southern blue flag | Up to 6 inches | Iris virginica (southern blue flag iris) |
| Full sun | Both types | Iris versicolor (northern blue flag) |
What pot plus soil work in water?
Colorado State says a heavy clay loam soil is the preferred medium for aquatic plants. Avoid peat, perlite, bark or other light materials that float. A pot 12 inches across plus ten inches deep fits most aquatics. Moisten the soil first plus pot plants in a shaded area. Colorado State says marginal plants go near the center of the container with the crown just above the soil.
Clay loam: stays put. No peat or perlite: light mixes float. 12 by 10 inch pot: most aquatics.
How do you place iris in a pond?
NC State says southern blue flag can be left in water over winter and works in pond borders. Northern blue flag reaches 2 to 2.5 feet tall with blue lavender to white blooms. LSU AgCenter says Louisiana irises need at least six hours of direct sun for good blooming. Plant them at the same level they grew in the container and about 12 inches apart.
Winter: can stay in water. Six hours sun: good bloom. 12 inches: plant spacing.
Troubleshooting
Soil floating out of the pot? Colorado State says to skip peat, perlite plus bark.
Few blooms? LSU AgCenter calls for at least six hours of direct sun.
Leaves drying at the tips? NC State says southern blue flag should not dry out.
Kind Seed Co shares these plant notes for growers of all kinds. For more on growing in water see hydroponic growing in different mediums and pond water for cannabis. Read caring for your hydroponic system for system care. See garden microclimates for cannabis for site notes.
Sources
- Iris versicolor (northern blue flag), NC State Extension Gardener Plant Toolbox
- Iris virginica (southern blue flag iris), NC State Extension Gardener Plant Toolbox
- Add beautiful Louisiana irises to your garden, LSU AgCenter
- Water gardens: planting aquatic plants (PlantTalk 1026), Colorado State University Extension
FAQ
How deep should water iris sit?
NC State says northern blue flag takes up to 4 inches of water. Southern blue flag takes up to 6 inches.
Can water iris stay outside in winter?
NC State says southern blue flag may be left in water over winter.
Do Louisiana irises need full sun?
LSU AgCenter says at least six hours of direct sun is needed for good blooming.
What soil should go in an aquatic pot?
Colorado State says heavy clay loam. Avoid peat, perlite plus bark since they float.
What size pot do aquatic plants need?
Colorado State says 12 inches across plus ten inches deep fits most aquatics.
