Pacific Coast iris enhance the beauty of any rockery or border where they are planted.
These lovely species, native only to a strip of our Western coast from lower Washington to California, are becoming increasingly popular with gardeners interested in small irises.
Not to be confused with miniature or dwarf types, these Apogon (beardless) family members are short-stemmed with small orchid-like flowers and attractive foliage.
They are not difficult to maintain if proper care is used when planting rhizomes or seeds. In recent years, much has been done to bring the best of this iris to ultimate perfection through hand pollination.
To Dr. Lee W. Lenz of the Rancho Santa Ana Botanic Garden, Dr. Quentin D. Clarkson and Dr. Matthew Riddle must get credit for the fine Pacific Coast irises now available to gardeners.
Hybridization of Plants
When the American Iris Society held its 1960 convention in Portland, visitors were impressed with the extensive plantings in Dr. Riddle’s iris gardens.
His careful selection and hybridization of plants over the past 20 years are noteworthy. He collects his plants in the spring since growth begins in March and continues through May.
The small, slender rhizome roots can store only a small amount of food and must be lifted during spring growth or after September when growth is again underway.
If you dig your own (in the areas where this is not restricted), shake the soil off carefully to rid the rhizomes of weed seed and debris.
Wrap them in wet peat moss, then in a newspaper, and wrap them tightly with a rubber band. If you buy, patronize a reliable horticulturalist who digs when the time is ripe.
Plant the rhizomes approximately below the surface. If planting seed, sow seed which germinates rapidly.
In time, the plants will sow their seed which may be gathered for future use. For best results, the soil should be acidic. Otherwise, an iron compound must be added.
The seed should be placed ¼” deep. The germination period varies; sometimes, it is during the first year, or it may take five years.
Enhancement of Germination
Bloom may be expected 18 months from the time plants appear. However, winter freezing enhances germination, which, as a rule, begins the following April.
Young plants should not be lifted until the following spring when root growth begins again.
This is important and the reason why some collectors, both amateur, and commercial, lose their plants.
If you wish to save seed, pick the capsule after it opens. Seed mold may be avoided by spreading the seed out in a cool, dry place.
Protection of Young Plants
Drying takes two or three days, after which the seeds may be shaken out. Finally, they may be planted outside in September.
Young plants need protection from birds and small animals until they are well established.
Seeds retain their viability for several years, so it is better to wait for the proper time and to have the proper location before planting.
Bees may be foiled by removing their landing fields—the outer, broad, and spreading divisions of the perianth (falls).
Favorite Hybridizing Types
Dr. Riddle’s favorite hybridizing type is innominata, because of its usefulness in developing better strains.
In its natural state, it hybridizes readily with such other species as douglasiana, Tenax, chrysophylla, and gormani.
Many plants collected around the periphery of innominata are natural hybrids and exhibit different colors.
Most of the Pacific Coast irises growing in his garden show distinct characteristics of this species.
Classification of Different Species
Following are Dr. Lenz’s classification of the different species, previous to which identification was difficult—
- I. tenuis—resembles the Oriental iris; its flowers are white, marked with yellow and purple, miniature in size, as are the leaves; it will not hybridize
- Tenax—flowers light rosy-pink to deep purple, blooms when there are not many purple flowers, prefers dry, sunny locations similar to native uplands
- Chrysophylla—prefers dry location. Bowers tan and yellow
- Bracteata—prefers dry location, flowers yellow
- Gormani—shades of yellow, likes moisture and some sun;
- Purdyi—prefers a cool climate, flowers are pale cream;
- Innominata—shades of yellow basically, but natural hybridizing produces browns, reds, and pinks;
- Douglasiana—flowers lavender into blue, likes moisture but not too much shade;
Disease Courier
Thompsoni is not a species but one of the color variations with shades of lavender into blue with an occasional rare white.
Pacific Coast irises harbor no pests, nor do they carry disease. So, if your winters are not too rigorous and your summers not too moist (during the dormant season), you will be repaid for the comparatively easy culture of these colorful garden gems.
44659 by Marguerite N. Davis