Among the most popular water garden plants, these irises are valued for their elegant beauty and simple, uncluttered form. With their clean, vertical lines and striking sword-shaped foliage, they’re attractive even when not in bloom.
Easy to grow and versatile, water-loving irises are suitable for a variety of situations: some prefer growing in the shallows at a pond’s edge, others in a moist spot in the garden, while many can be plunged into the depths of a pond or in a water-tight half-barrel. Each type has different moisture, cultivation and maintenance requirements. And as with other marginal plants, their roots act as excellent biological filters, cleaning the water of excess nitrogen, contaminants and algae.
Water-loving irises are beautiful, easy-to-grow plants. Their exquisite flowers comprise falls (three lower sepals), standards (three upper petals), style arms (modified pistils) and signals (contrasting colour patches on the falls).
Harvesting iris seeds
To harvest seeds, let pods dry naturally and split open; many iris seeds float on the water when ripe. Plant seeds in a small pot filled with potting mix; moisten and enclose container in a sealed, clear plastic bag; place in the refrigerator to stratify. After 90 days, take out of refrigerator and remove plastic bag (germination can take up to 60 additional days). Plant seedlings outdoors in the spring; they may take up to two years to bloom. Note that some irises do not reproduce true to type from seed.
- Plant in full sun (for better foliage colour and flowering) to part shade.
- Grow in consistently moist, rich, loamy soils or partially or completely submerged in ponds. (See page 3 for depths for specific types.)
- For plants growing in pots in a pond or half-barrel, add a pea gravel mulch to keep soil in place under water.
- Feed with an aquatic plant fertilizer in the spring before flowering and again after blooms fade.
- Deadhead to prevent self-seeding unless collecting seeds for propagation or seed pods for decoration.
- Divide rhizomes either before or after flowering (but before the end of July). Some container-grown water irises may need dividing every year to prevent overcrowding of rhizomes. (Wear gloves to avoid contact with plant sap, which may irritate the skin.)
- After the first frost, trim the leaves to about three centimetres above the crown.