Our native Pacific Coast irises include 11 species that produce flowers in shades of white, yellow, pink, lavender, even USC-worthy cardinal and gold.
Most of the Pacific Coast irises, or Pacificas, sold in California are from a single species, Iris douglasiana.
To learn about the foliage and flower distinctions behind each species classification, there is no better source than the Society for Pacific Coast Native Iris. Comprehensive breeding among species in the wild and in gardens make typing irises expert territory. You’ll know a true buff when he or she wonders aloud if the delicate Del Norte County iris might be not be responsible for the telltale luminosity of the yellow in one flower, or if the lineage of Munz’s iris, left, lies partly in the true blue of another.
Clashes can emerge when mixing native Pacificas with the exotic bearded irises sold in garden centers. I have done this, and the imports can do just fine on a water diet, like the natives. But keep in mind that bearded irises are often bigger. Leaves in established plants can seem almost sword-sized. Their flowers can seem huge, outlandishly frilly or too brightly colored.
Pacificas tend to be small and elegant. Their slender leaves look more like clumping grass. To my mind, this understated quality makes the native irises a far better fit for a woodland or meadow garden.
The differences continue below ground. The rhizomes of the bearded irises are far tougher than those of our natives. The toughest beards can be yanked from the ground, trimmed of foliage, put in a padded envelope, sent to a faraway aunt, left on the doorstep for a week and still end up upstaging everything else in her garden.
By contrast, Pacificas might not forgive you if their small white roots were left exposed to heat or air for more than a few minutes. It helps to know that rhizomes only produce small, tender white roots in late fall, usually mid-November to early December usually. Like the rest of our native wildflowers, the root system and foliage will then grow during the cool, wet months of December, January and February before exuberant flowers appear in spring.
Genus: Iris (EYE-ris) (Info)
Species: douglasiana (dug-lus-ee-AN-uh) (Info)
Class: Pacific Coast Native (PCN)
Height: 12-18 in. (30-45 cm)
Spacing: 24-36 in. (60-90 cm)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)
USDA Zone 9a: to -6.6 °C (20 °F)
USDA Zone 9b: to -3.8 °C (25 °F)
Sun Exposure: Sun to Partial Shade
Danger: Parts of plant are poisonous if ingested. Handling plant may cause skin irritation or allergic reaction
Bloom Color: Dark Blue, Blue-Violet, Violet/Lavender, Purple
Bloom Time: Late Midseason (MLa), Very late (VLa)
Other details: Average Water Needs; Water regularly; do not overwater
Soil pH requirements: 6.1 to 6.5 (mildly acidic), 6.6 to 7.5 (neutral), 7.6 to 7.8 (mildly alkaline)
Patent Information: Non-patented
Propagation Methods: By dividing rhizomes, tubers, corms or bulbs (including offsets)
Seed Collecting: N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed
Read more: http://davesgarden.com/guides/pf/go/879/#ixzz3HhBxKCUf