Of the fifteen or so Iris that are native to the whole of the west coast, seven are at home here in Oregon. Most are known as “grass iris,” because their narrow leaves grow in a narrow-bladed grass-like clump, rather than the more distinctly separate, wider blades of their relatives (one exception is I. tenuis, which a “crested iris,” having the telltale ridge or “crest” along the center of it’s curved petal). They are also typically lower-growing than their non-native counterparts – generally not reaching any taller than 18 inches.
Most of our native species can be found west of the Cascades, from Washington southward into northern California; colorful drifts in primarily open, wooded areas at low elevations. So in the garden they will be happiest in part to full sun in well-drained soil. Others, native to parts of southwest Oregon and the grasslands east of the Cascades, can be beautiful additions to a rock garden or other dry spots. Blooming in the spring and going dormant in the summer, they like regular moisture through their bloom cycle then allowed to go dry, like the parts of the state from which they originate.
The flowers, rising gracefully above the foliage on slender stems, wear colors ranging from deep bluish purple to lavender to yellow to white (or varying combinations of these), generally with dark purple veining. Freely cross-pollinating, in areas where two or more species grow adjacent to each other naturally-occurring hybrids occur.
Slugs enjoy the leaves of the natives just like other Iris, but otherwise these jewels of the garden are relative problem-free.
I. douglasiana - Douglas’ Iris – the only evergreen native iris – found from southern Oregon to central California. Can tolerate sun or shade and somewhat drier conditions than its brethren. Flower color ranges from light blue-violet to dark purple, occasionally white.
Special thanks to the Society for Pacific Coast Native Iris for use of their information and photographs. For more information, please visit the Pacific Coast Native Iris Website
FACTS: NW NATIVE IRIS
Common name: Iris
Native Range: several native species of Iris found throughout our region, both sides of the Cascades, at various elevations.
Characteristics: The native Iris has the classic grassy, strap-like leaves, with delicate flowers rising above, ranging in colors from white to yellow to purple to reddish, and combinations of one or more of these colors. Different species that grow together in the same habitat often cross-pollinate of their own accord as well, so there is a wide variation of color combinations within this palate!
Culture: Sun to partial shade, seasonally to mostly wet to dry, depending on species and location. All prefer well-drained soil.
Pests/Diseases: slugs are fond of the foliage of some native iris, but generally problem free.