Pond Plants 2: Iris
Water Iris include a multitude of species and colors. All of the water iris are bog and marsh plants, but these water-loving plants can survive periods of dry soil. Iris are very hardy, and will grow in full sun to part shade. They possess long, blade-like leaves of green, sea green, or white and green stripes. Iris grow from a thick, root-like modified stem called a rhizome. To divide iris simply split the rhizome and repot. Plant iris in Hagen’s Pond Baskets or planting bags to allow their roots access to nutrients in the pond water.
Iris will compete with algae for these nutrients, reducing algae blooms. Use a heavy aquatic planting media such as Hoffmans Water Garden Soil or Microbe-lift Aquatic Planting Media. Iris can be fertilized once a month with fertilizer tablets (TWG2714) to encourage growth and blooms. These lovely pond plants will bloom almost without fail every April or May. A similar shaped plant, Acorus, can be potted like iris in the water garden. Acorus and smaller iris varieties are suitable choices or bog filters or beach areas in ponds. Iris and Acorus both provide interest and beauty to the water garden and create lovely backdrops for shorter, more delicate plants.
Yellow water iris, Iris pseudacorus, is a very robust, fast-spreading iris. Native to Europe and western Asia, yellow iris is hardy in zones 4-9. This tall, yellow-blooming plant achieves heights of 2-3 feet and can easily grow in 1-1 1/2 feet of water. The Louisiana Iris (various Iris species) also grow to 2-3 feet, but do best in 4″-12″ of water. Louisiana iris are native to Louisiana and southeastern U.S. wetlands. Many color varieties are available, including Black Gamecock (dark purple), Sea Wisp (pale blue), and Prof. Claude (red-violet). Louisiana iris species are cold hardy between zones 4-10.
Another southern native, the Red Iris, Iris fulva, produces beautiful, coppery-red flowers. The red iris is much shorter than the other water iris species, growing to about 18″. It is hardy from zones 5-11 and prefers shallower waters of about 4-6″. Japanese and Variegated Japanese Iris, Iris laevigata and Iris laevigata variegata, hail from Japan and eastern Asia. Both varieties possess purple blossoms, but the variegated Japanese iris has striped leaves. Both are hardy between zones 4-9 and grow from 2 to 3 feet in height. Siberian Iris, Iris siberica, is a native of northern Asia and eastern Europe. This tough plant is hardy down to zone 3 and grows taller than 2 feet.
The genus Acorus encompasses a group of plants similar in growth and planting needs to the iris. Acorus species do not have showy flowers like the iris, but they do provide interesting foliage. Two striped varieties are variegated sweetflag, Acorus calamus variegatus, a native of North America that grows to heights of 3 feet, and dwarf variegated sweetflag, Acorus gramineus variegatus, a Japanese and east Asian native that only reaches 12″ in height.
For more information about pond plants and potting:
- Aquarium Connection Pond Solution #2a
- Aquarium Connection Pond Solution #9
- Aquarium Connection Pond Solution #10a
- Aquarium Connection Pond Solution #10b
- Aquarium Connection Pond Solution #10c
- Aquarium Connection Pond Solution #21
- Article: Bog Filters
- Article: Made in the Shade