Water Iris

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Adding aquatic iris to any water garden or pond is a great, rewarding addition. Their thick, sword-shaped leaves and large flower petals come in many colors (yellow, purple, white, blue and lavender). Water iris provide color seasonally and serve a purpose and provide benefits ecologically to your outdoor environment. At Puget Sound Ponds, we offer an assortment of Irises. Plants are shipped bare root directly from our grower's via express shipping method.

What Is Water Iris?

A group of species of irises and cultivated varieties that prefer (or at least tolerate) to be submerged in shallow waters or due to the soggy soil, as opposed to regular garden irises. The majority of the most commonly cultivated varieties are found in ponds. Examples of popular water iris varieties are:

• Iris spp. or Louisiana iris can grow up to 4 inches of water; many of these varieties come from the Louisiana area where they have hybridized into a beautiful spectrum from red through the deepest shades of purple.
• Iris laevigata is known as a true aquatic plant and prefers shallow ponds for its survival. It will remain in water without any problems.
• The Japanese Iris will thrive in bog soil but should not be submerged for more than two months each year.
• The blue flag iris (Iris versicolor), has very beautiful blue-purple flowers; it's excellent for fish ponds.
• Pond iris (also called bog iris), is used as a general term to refer to any species of iris that will grow in a wet margin or pond shelf area.

The major difference between an iris that grows in a pond versus an iris that grows on land is how much water each type can handle. Irises that grow in soil need to stay dry because their roots will rot if they sit in water for too long. Conversely, irises that grow in water can thrive while their roots are submerged under water, which makes them ideal for planting along the edge of a pond or in a bog garden.

Why Plant Water Iris in Your Water Garden?

Water iris isn't simply attractive but also contributes significantly to your pond's ecosystem. Many pond owners have commented on how effective water iris are at performing a variety of functions.

• Natural filtering: The long, dense root system of the water iris readily absorbs excess nutrients and works to maintain clearer water in your pond.
• Habitat for Wildlife: The vertical vegetation of water irises creates shelter for frogs, beneficial insects (including some pollinators - bees, butterflies) and small fish. Blue flag irises, in particular, attract a great deal of pollination from other insects.
• Vertical Structure: Water irises can grow 18" - 40" tall, creating a dramatic vertical contrast with the horizontal growth of other aquatic plants, such as lily pads or water lilies, as they are normally associated with both lotus and lily pads.

Pond iris require little maintenance after they're established. Divide clumps every three to five years in the fall to maintain vigour. Pond iris will add year-round interest to your water garden even when they are not in bloom. Their sword-like green foliage provides a clear structure in your water garden from spring to fall.

Planting Water Iris in a Pond

Where to Plant

Water Iris can be placed on shallow shelves within your pond, generally between 4 and 12 inches of water depth and based on their variety, in order to keep them in the correct growing conditions. The Louisiana Iris and Laevigata cultivars tolerate the greatest depth of water. The Japanese Ensata Iris prefers to be at water's edge where the soils are wet/boggy, but not subject to standing water for an extended period of time.

To plant irises in a pond that does not have a planting shelf, place aquatic baskets (filled with pond soil) in the pond. Position the basket so that the crown of the iris sits at or slightly underneath the surface of the water.

How to Plant Irises in A Pond (Directions)

• Select a site that receives at least six hours of direct sun every day.
• Put a rhizome into a planting container made specifically for plants growing in water (basket type). These kinds of baskets should hold a heavy / fast-draining soil like loam or pond soil. It'll float if it has regular potting soil in it, and the water will become cloudy due to soil being released from container while submerged.
• The top of the pile of dirt should be level with water; the new growth will be facing towards the sky and out of the water. If placing the basket where it is to sit is not possible on the pond shelf by lowering it, you will have to use bricks to get it to sit at the correct depth.
• To ensure that fish do not disturb the roots, cover the soil with gravel.
• Do not fertilize for the first 4 to 6 weeks; allow the plant to settle before feeding with aquatic fertilizer tablets.

Planting Water Iris in Wet Soil (Non-Pond Settings)

The water iris grows well in rain gardens, creek beds, wet ditches, and continuously wet areas. If you plan on planting your irises in wet conditions or if you have an area outside of your garden where you want to grow irises, keep the soil moist and do not allow it to dry out during the summer months. The purple water iris or blue flag iris are excellent choices for planting in wet soil areas around the edges of ponds.

Water Iris Care Guide

• Sunlight Requirements: Full Sun to Partial Shade; 6+ Hours of Sunlight for Optimal Flowers
• Water Level: Varies by Variety Between 0" and 6" Deep
• Fertilizing: Use Aquatic Fertilizer Tablets Twice Per Month During Growing Season
• Dividing: Every 3-5 Years in the Fall, Divides Wanted Plants, Decreases Overcrowding, and Increases Blooming
• Winter Care: Hardy in Zones 3-9 (Most Varieties); Trim Foliage to 3" Above Ground in Late Fall to Promote Healthy Growth During Dormant Period(s)
• Bloom Time: Late Spring or Early Summer; Varies Based on Zone and Cultivar.

Popular Varieties Available at Puget Sound Ponds

• Louisiana Water Iris: Comes in shades of red, purple, violet, and lavender. They are between 20 and 30 inches tall and flower from the early part of spring to the later part of spring each year. In addition to being one of the most desired types of pond irises, they can also be grown in a regular garden bed as long as you provide adequate amounts of water regularly.
• Purple and Blue Irises: All irises of the purple and blue colors are varieties of the same species, either as the laevigata or flag type, producing an outstanding and classic selection for any pond water-irises planting.
• Japanese Water Irises: Have beautiful summer blooming flowers with large, frilly petals; they do well when planted at the edge of a pond or in a wet boggy area but not planted directly under water.
• Water Iris / Bog Iris: Perennial and Viburnum Native to North America. Hardy Water Iris; plant at the edge of ponds, on lakeshores and wet sloped hillsides. Great for erosion control and naturalized landscaping.

FAQs - Water Iris

Can a water iris grow in a traditional pond?

Yes, most species of water iris are suitable for planting in the pond shelf at 4 to 12 inches deep. Louisiana Iris and Iris laevigata are the best for prolonged submersion and can be used in containers directly in the pond or shallow planting areas.

How deep should water iris be planted in a pond?

The varieties of iris from Louisiana and laevigata can grow in water a maximum of four inches deep. The Japanese version of ensata iris can tolerate boggy dirt but should not be underwater for long periods of time. Blue flag iris and other types of bog iris will grow best if they have 2-6 inches of water around them, such as at the shore of a pond.

Are water irises safe for koi ponds?

Indeed, water irises are generally safe for humans and are frequently cultivated in koi ponds. The thick roots also help filter out aquatic nutrient sources that promote algae growth, thus improving koi pond water quality. Koi may occasionally eat newly grown plants if protected by gravel covering the top of a planting container.

What is the difference between pond iris and regular iris?

Bearded iris standard varieties require good drainage—if you put one in standing water, it will rot! Pond irises (Louisiana iris, blue flag, and laevigata) were bred to thrive in wet conditions—some even tolerate being under water for some time. The foliage may look similar, but their habitat requirements are quite different.

When do water irises bloom?

Most of the types of water iris will blossom from Late Spring into early Summer (4-6 In Western Hemisphere of this time frame depending on your hardiness zone). Generally speaking; the warmer your zone, the earlier you will have bloom. On the other hand, the Japanese types tend to flower later than other types, so most bloom in early summer.

How do I plant irises in a pond without a basket?

If your pond has a natural soil bottom, you can place your plant directly into the pond substrate. When doing so, ensure that the rhizome is placed into the muddy substrate, with the growing tip facing up, so it will grow toward the sun. In lined ponds, it is highly recommended to use baskets for planting, as this will help contain the roots and make it easier to divide up your plants at a later date.

Do water irises come back every year?

Indeed, a water iris becomes established in either a pond or lake and the majority of varieties can endure winter in Zones 3 to 9 per the USDA. The Louisiana iris has a winter hardiness of Zones 6 through 9. The blue flag and laevigata varieties will do well in the colder areas of Zones 3 through 5. Both types of irises must be cut back after the fall or they won't come back in the spring.