Resource Guide:Pacific Coast Iris

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Kathleen Sayce

Topics: Archive, Plants You Need

Pacific Coast iris blooming in spring. Photo: courtesy of Wild Ginger Farm

Pacific Coast iris (Iris, beardless section Californicae and cultivars, Iridaceae)

History: Pacific Coast iris are native to the West Coast, from Southern California to southwest Washington, in and west of the Sierra Nevada, Cascade, and Coast ranges. Highest diversity of species is in Northern California and southern Oregon. First cultivated and hybridized in England in the late 19th century from species seed collected in California. In the early 20th century, gardeners in California and Australia began to hybridize, starting with wild seeds from I. douglasiana and I. innominata.

Best features: Evergreen plants with brilliant jewel-toned flowers in a wide color range with intricate patterning. Suitable for border planting at the front to middle of the beds, for dry meadows with one annual fall mowing, or open woodland gardens with partial to full shade. Generally disease resistant with little annual maintenance needed to keep in good condition. Deer do not find PC iris palatable, though they will eat the occasional flower bud or tug out a seedling to taste. As with other irises, slugs and snails eat flowers but do not damage the vegetative parts of the plants.

Hardiness: Zones 6–10. On the West Coast, PC iris are grown widely in gardens from southern British Columbia to Southern California, west of the Cascade and Sierra Nevada ranges.

Conditions: Pacific Coast iris require well-drained, acidic soils that are damp to wet in winter or buried under snow, and somewhat moist to dry in summer. They prefer full sun along the Northwest coast, to full shade in very hot dry climates. In the Central Valley of California, they need shade and summer water. PC iris flower best if divided every three to five years. Optimal planting and transplanting times are late fall to winter and early spring to late spring; to improve success, check for fresh white roots before transplanting. Fertilizers should be acidic.

Bloom time: Late winter to early summer, with a few cultivars flowering mid-winter, and some in July. The occasional plant reblooms in fall.

Iris Innominata. Photo: Lewis & Adele Lawyer — *Iris Innominata*. Photo: Lewis & Adele Lawyer

Species: Douglas iris (Iris douglasiana) grows along the coast from southern Oregon to southern California in coastal meadows in the salt-spray zone. Colors range from white, yellow, pink, blue, and lavender to purple, usually with a yellow signal.

Golden iris (Iris innominata) is native to southern Oregon and extreme northern California. It has yellow to golden flowers with dark veins and is hardier than most PC iris species. The first named PC iris selection, ‘Aureonymphe’, was an Iris innominata selection in England.

Tough-leaved or Oregon iris (Iris tenax) is native to Oregon and southwest Washington. Like I. douglasiana it has a very wide range of flower colors and like I. innominata is very cold tolerant. Falls usually have darker veins with a gold to yellow signal.

Playing Favorites

PC iris typically flower from seed in two years, so new plants and hybrids can be developed relatively quickly. There are hundreds of hybrids available. Current hybridizing programs in the US and Australia now grow new PC iris cultivars that are 50 or 60 generations removed from the original species, with color and patterning more spectacular with each generation. The following list of hybrids is a very brief introduction to this colorful section of iris:

–‘Blue Plate Special’: light blue with a dark blue halo, blue veins, and a yellow signal. Photo: Ken Walker — – ‘Blue Plate Special’: light blue with a dark blue halo, blue veins, and a yellow signal. Photo: Ken Walker

–‘Broadleigh Sybil’: rose falls, dark rose halo, yellow signal, and light rose standards and style arms. Photo: Jay & Terry Hudson — – ‘Broadleigh Sybil’: rose falls, dark rose halo, yellow signal, and light rose standards and style arms. Photo: Jay & Terry Hudson

‘Canyon Snow’: white flowers with a gold blotch on falls. Photo: Richard C. Richards

‘Cashing In’: yellow and very ruffly. Photo: Ken Walker

‘Curlique’: ruffly, wide purple and white petals with a yellow signal and streak. Photo: Ken Walker

‘Distant Nebula’: lavender with dark purple signal and veins. Photo: Ken Walker

‘Dracularity’: ruffled red falls with white rim, dark red veins and black signal, red standards with light gold and red style arms. Photo: Richard C. Richards

‘Drip Drop’: purple with a white halo and yellow signal. Photo: Ken Walker

‘Egocentric’: rose falls with yellow cream and red signal, yellow cream style arms and rose standards. Photo: Debby Cole

‘Eyes Have It’: rose purple with darker veins and signal and a yellow streak. Photo: Ken Walker

‘Fallen Plums’: dark rose purple falls with lighter rose standards and white style arms. Photo: Ken Walker

‘Mendocino Blue’: blue flowers with slightly darker wisteria-blue falls, darker blue halo and veining, and turquoise mid-rib wash; signals are lighter hyacinth- blue with darker veining. Photo: Jay & Terry Hudson

‘Mission Santa Cruz’: rosy red-magenta flowers. Photo: Ken Walker

‘New Blood’: very dark red with a lighter signal and yellow style arms. Photo: Ken Walker

‘Oxymoron’: ruffled, deep henna falls have a neon violet signal and yellow style arms. Photo: Ken Walker

‘Public Eye’: white with dark purple veins and signal, white standards, and purple style arms. Photo: Bob Seaman

‘Vain’: pale yellow with darker veins and white signal. Photo: Ken Walker

‘Valley Banner’: white with dense purple veins on falls, white standards, and purple style arms. Photo: Richard C. Richards

Get Growing

The Society for Pacific Coast Native Iris (SPCNI) advances the study and cultivation of Pacific Coast iris. SPCNI maintains a registry of hybrids and hosts an annual online seed sale for members. SPCNI also posts descriptions of species and information about growing PC iris. www.pacificcoastiris.org.

Species Iris Group of North America (SIGNA) includes PC iris in its annual seed sales, and has photos of several species and hybrids in the online iris species gallery. www.signa.org.

American Iris Society (AIS) includes PC iris species and hybrids in an online iris encyclopedia; each entry includes photos and descriptions. This encyclopedia is quickly becoming the go-to place for online information on iris species and hybrids. For more information see www.irises.org.

Many nurseries in the west offer at least a few plants, and many nurseries offer several registered varieties and their own seedlings, including:

Leonine Iris Nursery, Seattle, Washington, www.leonineiris.com

Cascadia Iris Gardens, Woodinville, Washington, www.cascadiairisgardens.com

Wild Ginger Farm, Beavercreek, Oregon, www.wildgingerfarm.com

Bay View Gardens, Santa Cruz, California

Matilija Nursery, Moorpark, California, www.matilijanursery.com

A number of seed companies offer seeds of one or more species; many of these are unregistered hybrids. Plants are available at many iris nurseries and native plant nurseries. An annual list of those nurseries offering more than 4 species and 10 registered hybrids is printed in the SPCNI publication, Pacific Iris.