Yellow flag iris Iris pseudacorus

☠ Toxic to humans
🐾 Toxic to pets
🌸 Blooming
🍪 Not edible
‍🌱 Easy-care
yellow iris


The plant known as yellow iris is a strikingly vivid perennial that displays a hardy nature with its thick, deep green, sword-like leaves that form a dense clump, emanating from a robust root system. These leaves arch gracefully and have a distinctively sharp appearance. The eye-catching feature of the yellow iris is its flowers, which are large and showy with vibrant yellow petals. Each blossom is comprised of three drooping sepals adorned with brown or purple veining, which are often referred to as "falls," and three upright petals, called "standards," creating a unique and appealing contrast. The yellow iris is commonly found near wet areas, and its flowers bloom mainly in the late spring to early summer, depending on the regional climate. The plant also produces fruit capsules that are elongated and contain numerous seeds, which allow for its distribution and growth in suitable environments. The overall visual impact of the yellow iris is that of a lush, striking plant that enlivens water margins and wetlands with its bright flowers and robust foliage.

Plant Info
Common Problems

About this plant

  • memoNames

    • Family


    • Synonyms

      Yellow Iris, Water Flag, Paleyellow Iris, Yellow water iris, Yellow-flag, Yellow-flag iris.

    • Common names

      Iris paludosa, Limnirion pseudacorus, Pseudoacorus vulgaris, Xiphion pseudacorus.

  • skullToxicity

    • To humans

      Yellow iris, or Iris pseudacorus, contains irritating substances that can be toxic if ingested. All parts of the plant are considered poisonous, including the rhizomes and leaves. The principal toxic component is believed to be the glycoside iridin, which can cause digestive upset, such as nausea, vomiting, abdominal pain, and diarrhea. Other symptoms may include irritation of the skin and mucous membranes. Ingesting large quantities can result in more severe health issues, including potential damage to the liver and kidneys. It is crucial for humans to avoid consuming any part of the yellow iris to prevent these toxic effects.

    • To pets

      Yellow iris is also toxic to pets. All parts of the plant, particularly the rhizomes, contain compounds that can cause gastrointestinal irritation if ingested. The symptoms of poisoning in pets are similar to those in humans, typically including vomiting, diarrhea, excessive salivation, and abdominal pain. In some cases, pets might exhibit signs of dermatitis if they come into contact with the sap. It is important for pet owners to ensure their animals do not chew on or ingest any part of the yellow iris to avoid these toxic effects.

  • infoCharacteristics

    • Life cycle


    • Foliage type


    • Color of leaves


    • Flower color


    • Height

      2-3 feet (60-90 cm)

    • Spread

      2-3 feet (60-90 cm)

    • Plant type


    • Hardiness zones


    • Native area

      Europe, Western Asia


  • money-bagGeneral Benefits

    • Ornamental Value: Yellow Flag Iris, with its striking yellow flowers, is popular in gardens and landscape design, adding aesthetic appeal to ponds and water features.
    • Wildlife Habitat: The plant provides shelter and breeding grounds for a variety of aquatic animals including fish and amphibians.
    • Soil Stabilization: Iris pseudacorus has a robust root system that can help prevent soil erosion along water bodies.
    • Water Treatment: The plant is used in constructed wetlands for wastewater treatment, where it helps absorb excess nutrients from the water.
    • Education and Research: Yellow Flag Iris is often used in scientific studies and educational projects to understand wetland ecology and plant biology.
    • Ecosystem Support: It contributes to the biodiversity of wetland ecosystems by providing food and habitat for insects and other wildlife.
    • Cultural Significance: In some cultures, Yellow Flag Iris is associated with symbolism and is used in art, literature, and heraldry.

  • medicalMedical Properties

    • Diuretic: Iris pseudacorus has traditionally been used to promote the release of urine.
    • Laxative: It has been used to encourage bowel movements.
    • Emetic: The plant has properties that may induce vomiting when taken in large quantities.

  • windAir-purifying Qualities

    This plant is not specifically known for air purifying qualities.

  • leavesOther Uses

    • Iris pseudacorus, commonly known as yellow iris, can be used as a natural dye; the roots can yield a black dye, while the flowers can be used to make a yellow dye.
    • The stems and leaves of the yellow iris can be woven into baskets, mats, and other craft materials, providing a sustainable source of fibrous material.
    • In historical times, the yellow iris was used as a heraldic symbol and appears in the design of the Fleur-de-lis, representing royalty and nobility.
    • The plant has been used in water filtration systems, as it can absorb heavy metals and other pollutants from water bodies, improving water quality.
    • The seeds of yellow iris have a buoyant property, enabling them to be potentially used as a natural filling for life preservers or floatation devices.
    • Yellow iris can be planted on the banks of rivers and streams to prevent soil erosion due to its robust root system that stabilizes the ground.
    • The plant is often used in ornamental ponds and water gardens for its striking yellow flowers enhancing aesthetic beauty.
    • Yellow iris plays a role in the crafting of perfumes, with some components of its scent being used in the perfume industry.
    • In some regions, the dried seed pods of the yellow iris are used in floral arrangements for their unique appearance and texture.
    • Because of its extensive root system, the plant can also be used for land reclamation projects to help establish vegetation on disturbed soil.

Interesting Facts

  • bedFeng Shui

    The Yellow Iris is not used in Feng Shui practice.

  • aquariusZodiac Sign Compitability

    The Yellow Iris is not used in astrology practice.

  • spiralPlant Symbolism

    • Purity: The iris's vibrant flowers are often associated with purity, perhaps due to their striking appearance and delicate structure.
    • Royalty: The iris has been a symbol of royalty and regal bearing, likely influenced by its use in heraldry and its association with the French monarchy, especially the fleur-de-lis.
    • Wisdom: This flower can represent wisdom, echoing the Greek goddess Iris, who was a messenger for the gods and a symbol of communication and messages.
    • Hope: The iris embodies hope, with its blooms signalling the beginning of spring and the return of brighter days.
    • Faith: In religious contexts, the iris is seen as a symbol of faith, trust, and belief.
    • Valor: The durability and resilience of the iris allow it to symbolize valor and courage in adverse situations.

Keep soil moist
500 - 2500 Lux
Every year
Spring to summer
As needed
  • water dropWater

    Yellow flag iris thrives in wet conditions and does not require traditional watering if planted in a pond or bog. If it's in a container without standing water, keep the soil consistently moist by watering it with about one to two gallons per week, depending on climate conditions. During hot, dry periods, it may require more frequent watering to maintain the moisture level, but be cautious of waterlogging the soil in non-aquatic settings.

  • sunLight

    Yellow flag iris performs best in full sun to partial shade. Ideally, plant it in a location where it receives at least six hours of direct sunlight daily. It can tolerate light shade, but blooming may be reduced in less than optimum light conditions.

  • thermometerTemperature

    Yellow flag iris is hardy and can survive in temperatures as low as -30 degrees Fahrenheit and as high as 90 degrees Fahrenheit. The ideal temperature for vigorous growth is between 50 and 75 degrees Fahrenheit. This plant can tolerate seasonal temperature fluctuations well and is suitable for many temperate climates.

  • scissorsPruning

    Prune yellow flag iris to remove spent flowers and encourage a second bloom. In late autumn, cut back dead foliage to tidy the plant and promote healthy growth for the next season. It's best to divide and prune every three to five years to maintain vigour and control the spread, especially in smaller ponds or gardens.

  • broomCleaning

    As needed

  • bambooSoil

    Yellow flag iris thrives best in a soil mix that has high organic matter content and is well-aerated. The ideal pH for yellow flag iris is slightly acidic to neutral, around 5.5 to 7. A mixture of garden soil, compost, and peat with some sand for drainage can create an appropriate environment for this moisture-loving plant.

  • plantRepotting

    Yellow flag iris should be repotted every two to three years to prevent overcrowding and promote healthy growth. It's best to divide the rhizomes during repotting and remove any dead or rotting material to encourage new shoots to form.

  • water dropsHumidity & Misting

    Yellow flag iris is not particularly humidity-sensitive and can tolerate a wide range of humidity levels. However, they naturally grow in wet conditions and are commonly found in boggy areas or at the water's edge, indicating a preference for higher humidity environments.

  • pinSuitable locations

    • Indoor

      Grow yellow flag iris in a pot with moist, fertile soil and full sun.

    • Outdoor

      Plant yellow flag iris in water or damp soil, full to partial sun.

    • Hardiness zone

      4-9 USDA

  • circleLife cycle

    Iris pseudacorus, commonly known as Yellow flag iris, begins its life cycle as a seed that germinates in late spring to early summer, typically in standing water or very wet soil. The seedlings develop into juvenile plants and form rhizomes, which are horizontal underground stems that store energy and nutrients. Over the years, these rhizomes give rise to new shoots, and the plant matures, typically flowering in late spring or early summer. After blooming, it produces capsules containing numerous seeds that are dispersed by water or wildlife. The plant persists through its rhizomes, which continue to produce new growth each year, and it can also reproduce vegetatively by rhizome division. In winter, the above-ground foliage of Yellow flag iris dies back, but the rhizomes survive to sprout anew come spring.

  • sproutPropogation

    • Propogation time

      Spring to summer

    • Propogation: Iris pseudacorus, commonly known as yellow flag iris, is typically propagated in the spring or early summer when the plant's growth is most active. The most popular method of propagation for yellow flag iris is by division of its rhizomes, which are horizontal underground stems that send out roots and shoots. To propagate by division, carefully dig up the plant, making sure to keep a good portion of the root system intact. Use a sharp knife to cut the rhizomes into sections, ensuring that each section has at least one or two growing points, often identifiable by a fan of leaves or a bud. Replant the rhizome sections at least 12 inches (about 30 cm) apart in a location with full or partial sun and in wet or moist soil, as yellow flag iris thrives in boggy conditions. Water the newly planted divisions well to settle the soil and encourage quick root establishment.