Propagating Iris pseudacorus 'Variegata' by Rhizome Division

Divide the rhizome of variegated yellow flag iris to multiply this marginal pond plant. Note: it is emergent, not a submerged aquarium plant, and invasive in North America.

Overview

Iris pseudacorus 'Variegata' is the variegated form of yellow flag iris, a herbaceous perennial reaching 100-150 cm tall and native to Europe, western Asia and northwest Africa. It is a marginal, emergent bog and pond plant: it grows in very wet conditions and shallow water and tolerates submersion of the rootstock, but it is not a fully submerged aquarium plant. It spreads by rhizomes and by water-dispersed seeds, and tolerates a wide range from low pH and anoxic soils to high salinity.

Propagation Method

This iris is propagated by rhizome division. Its creeping rhizome is lifted and cut into sections, each carrying its own roots and a growing point, which are then replanted. Division is the reliable way to keep the cream-and-green variegation true, since seed-grown plants do not stay variegated.

Step-by-Step

Lift an established clump and rinse soil from the rhizome.
Cut the rhizome into sections, each with roots and at least one healthy fan of leaves.
Trim the leaves back to reduce water loss while the division re-establishes.
Replant each section at the pond margin or in a planting basket, with the rhizome just at or below the wet soil surface.
Keep the soil saturated or in shallow water until new growth appears.

Conditions for Healthy Growth

Marginal position in shallow water or constantly wet, nutrient-rich soil.
Full sun for best growth and the strongest variegation.
Tolerant of cool, temperate conditions and a broad pH range.
Grown emergent, with foliage in air, not as a submersed aquarium plant.

Maintenance

Vigorous clumps benefit from lifting and dividing every few years to relieve congestion and renew the variegated foliage. Because it can remove nitrogen and phosphorus from water, it works well in planting baskets that you can lift to control its spread. All parts of the plant are poisonous, so wear gloves when handling rhizomes.

Common Challenges

Uncontained rhizomes spread aggressively and rhizome fragments readily re-sprout.
Seeds float and disperse on water, so removing spent flowers limits unwanted spread.
Variegation can fade in shade; give the plant strong light.
It will rot if grown as a permanently submerged aquarium plant rather than as a marginal.