Propagating Sagittaria latifolia (Broadleaf Arrowhead)

How to propagate broadleaf arrowhead, or duck potato, using its stolon runners, starchy tubers and rosette division for dense emergent pond and marginal colonies.

Overview

Sagittaria latifolia, the broadleaf arrowhead or duck potato, is a robust North American emergent perennial. It grows in rosettes of leaves, typically reaching 60 to 120 cm and occasionally up to 150 cm, with highly variable arrow-shaped blades 10 to 50 cm long whose parallel veins meet at the middle and the tip.

It is a fast-growing root feeder used as a classic pond and marginal plant. Propagation relies on its runners, tubers and division of the rosette rather than on stem cuttings.

Propagation Method

The plant spreads vegetatively through runners (stolons) at or just under the soil surface, forming dense colonies. In late summer the rhizomes also produce starchy tubers, 0.5 to 5 cm across and about twice as long as wide. These tubers, plus simple division of crowded rosettes, give three reliable routes to new plants.

Step-by-Step

1. For runners, locate stolons running through the substrate and lift sections that have rooted and begun a new rosette.
2. Separate each rooted plantlet and replant it in nutrient-rich substrate.
3. For tubers, harvest in late season; disturbed tubers usually float to the surface for easy collection.
4. Plant tubers about 5 to 7 cm deep in water depths of roughly 0.15 to 0.45 m.
5. For division, lift a crowded clump and split the rosette and rhizome into rooted pieces, replanting each separately.

Conditions for Healthy Growth

Arrowhead inhabits wet areas such as ponds and swamps, forming dense colonies on very wet soils. It shows an affinity for high phosphate levels and hard water, and as a strong root feeder benefits from a nutrient-rich substrate. It tolerates a wide temperature range, suiting coldwater ponds and marginal plantings, and prefers high light.

Maintenance

Given its vigorous spread, thin the colony periodically by removing runners and crowded rosettes so it does not overwhelm a pond margin. Lifted pieces and tubers are ideal propagation stock. Top up substrate nutrients for this hungry root feeder to sustain steady growth.

Common Challenges

Its fast runner growth can quickly form dense colonies that crowd smaller marginals, so containment in baskets helps in ponds. Buried tubers floating loose after disturbance can drift away before replanting, and in low light or lean substrate the tall emergent leaves grow weak. Regular thinning and feeding address both issues.