Sagittaria macrocarpa thrives in consistently moist to waterlogged conditions. Keep the soil saturated, as it is an aquatic or semi-aquatic plant. In ponds or water gardens, ensure the roots are submerged.

For container-grown plants, maintain a water level that covers the soil surface.

Pruning is generally minimal for Sagittaria macrocarpa. Remove any dead, yellowed, or damaged leaves and flower stalks as they appear to maintain the plant's health and appearance.

This also helps prevent disease and encourages new growth.

Propagation is easily done through division of rhizomes or by collecting and sowing the seed-like fruits. Rhizome division is best performed in spring.

Seeds can be sown in moist soil or shallow water after the last frost, providing they are viable.

Repotting is typically only necessary if the plant outgrows its container or becomes pot-bound, usually every 2-3 years. This is best done in early spring before new growth begins.

Use a heavy, watertight pot and a nutrient-rich aquatic soil mix.