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Plant Guide

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Iris douglasiana

  • Common Name
    Pacific Coast Iris
  • CA Native
    California Native
  • Plant Type
    Perennial
  • Size
    18" - 36" x 15" - 24"
  • Flower Color
    Blue, purple, White, Maroon, Yellow
  • Bloom Time
    • Spring
  • Leaves
    Green, Strap-Leaves
  • Evergreen
    Evergreen
  • Deer Resistant
    N / A
  • Wildlife Value
    • Bees
  • Growth Rate
    Fast
  • Hardiness
    Hardy
  • Adverse Growth Factors
    None
  • Special Features
    • Good Under Oaks
    • Low Maintenance
    • Showy Flowers
  • Water Use
    • Drought Tolerant
    • Low
  • Soil pH
    5.5-6.4 (acid)
  • Exposure
    • Partial Shade
    • Shade
  • Soil Type
    Not Particular
  • Drainage
    Good Drainage
  • Description and Cultural Plant Tips

    There are 11 species of native Pacific Coast Irises (PCI), one of which is I. douglasiana. I. douglasiana has been been successfully hybridized with other PCI in Ca., Washington and Oregon to produce stunning flowers of varying colors that can grow up to 1.5 feet tall. The collection of hybrids are often called Pacific Coast Hybids in the nurseries.

    In nature, they are found  in meadows and woodlands near the coast and do best in a mild, maritime climate. In gardens near the coast they will tolerate full sun, however, inland it is best to plant them in light shade during the hottest part of the day. While PCI's can grow in a whide range of soils, they prefer a slightly acidic (pH 5.5 - 6.5) soil to which considerable peat or humus has been added. Feeding should be done in the spring using a balanced slow release camellia/azalea fertilizer. Water once or twice a month in the summer once PCI is established. Mulching is recommended to conserve water in the root zone. They do tend to look a little ratty if no water is applied in the summer.

    PCI's resent being divided so it is best to let them grow undisturbed for a few years. When the clumps get large enough (2 -3 years) they can be transplanted successfully when their roots are actively growing in the late fall (after rain) or early spring. Check the roots to see if they are white and plump before you transplant. It is vital to keep roots moist when you are lifting and dividing them. Water immediately after transplanting  keeping moist until established.

    PCI's have few pests or diseases. However, if planted in areas with poor drainage, PCI's can develop rhizome rot and fungal or viral diseases. They can also be attached by aphids, slugs and snails.

  • Master Gardener Comments

    These irises do very well under oak trees inland since they do not require much water in the summer. I plant them with other natives such as Shooting Stars and Hounds Tongue for a pretty spring display.

  • Varietals

    I. douglasiana 'Amiuuita' - blue bi-tone with a purple single spot

    I. douglasiana ' Canyon Snow' - white

    I. douglasiana 'Harland Hand' - purple, long-blooming season

    I. douglasiana 'Mendocino Banner' - white with purple veins