Pacific Coast Or California Irises

They are known as Californian irises and this of course gives the clue to their place of origin. You probably wouldn't mistake a flower from this group for a bearded iris, but some look very similar to modern Siberian blooms and there are others that could easily be mistaken for a Louisiana. They hybridize very freely among themselves and, as with many other groups of iris, they have received a lot of attention from hybridizers. The many and often unaccountable hybrids are now commonly called Pacific Coast irises.

It is possible to find these plants growing wild along the Pacific Coast from southern California to Oregon on open grassy slopes and partially shaded hillsides, or on the ground beneath trees in a mixed forest.

One species, I. purdyi, is not much taller than a toddler's knee and grows in redwood forests in northwest California. The flowers are dainty and creamy white, finely overlaid on the falls with red-brown veining - it is difficult to imagine a more complete contrast between it and the dark conifers towering overhead.

Characteristics

The eleven species that make up the Californian class of irises are singular in that they all are native to the Pacific Coast states of California, Oregon and Washington. Their chromosome count (2n), the number you would find in any of the species, is 40-or 20 pairs of chromosomes. These irises generally are quite dwarf with unbranched flower stems, slender grassy leaves, tough rhizomes and wiry roots.

Exceptions to this are Iris douglasiana and especially I. munzii, which can produce flower stalks as tall as 3 feet. These two species also have longer, broader leaves. I. munzii doesn't branch but can produce four flowers per spathe. I. douglasiana branches and can produce three flowers per spathe. Crosses between these two species can produce branched flower stems with up to four flowers per spathe, a total of eight to eighteen flowers per stalk. With the exception of I. tenax and I. hartwegii, which are deciduous, the Pacific Coast native irises are evergreen.

I. douglasiana and I. innominata are the two species that serve as the backbone of contemporary Pacific Coast hybrids. I. douglasiana, with the widest distribution of all the Pacific Coast irises, grows easily and quickly from seed and has flowers of many colors, from white through azure through lavender and purple. I. innominata is particularly noted for its deep yellow and golden flowers. Both are worthy additions to gardens. I. innominata, native to Oregon, thrives under cool growing conditions and will not do well in other climates. Its grass-like foliage gives the plants a finely delicate look.

The most cold-hardy of the Pacific Coast irises is I. tenax, a native to the western side of the Cascade Mountains. It is also used in hybridizing programs. This iris, a deciduous species, grows into attractive clumps with many flowers. While these three species have played the major roles in modern Pacific Coast hybrids, the other species have been a part of some hybridizing programs, playing a much lesser part in the background of garden cultivars.

Plants of this class of irises grow in mountainous and open forested regions, with the exception that I. douglasiana grows near the ocean on windy bluffs and bare land that has recently been cleared. This is a widely grown Pacific Coast native iris, an excellent garden plant undoubtedly because of its wide range of adaptability. It also is geographically the most widespread of these irises. I. douglasiana will grow in well-draining gritty soils amended with compost or in heavy clay soils and is extremely vigorous. This species has leaves up to 1/8 inch in width and 12 to 40 inches in length. Flower colors range from cream to lavender to red-purple with occasional blue and albino forms. The plants form large circular mats of vigorous growth.

Pacific Coast flowers are iris like in character, with falls that flare rather than droop or curve down. The different species are quite variable, especially in their colors. In gardens, the species crossbreed easily, often producing handsome offspring.

Culture

This class of irises is well suited for gardens in its native lands. It is hard to find similar climates in the United States, climates like the West Coast where you can find places with close to six months without rain.

Gritty well-draining soil with plenty of organic matter and a pH that is within the range of slightly acid to neutral is what will suit Pacific Coast irises very well. It is likely that these irises will not do well where the soil has a pH that is above 7. 0. Protection from hot afternoon sun will be beneficial. A site that is on a moist slope or along a stream in a region where summers are long and dry will encourage these irises to thrive.

The best environment for these irises is one with cool, moist winters and long, dry, warm summers. The combination of hot sun and rain will encourage crown rot-plants in this type of climate are usually lost. Their growing cycle is such that they begin to grow when rainy fall weather arrives and reach their peak of growth in spring and early summer. After they bloom and set seed, they begin a dormant period during the dry summer season of their native lands.

Pacific Coast native irises are best transplanted before the plants reach their blooming period and well before they begin their summer dormant period. Dividing and transplanting while they are in active growth means that they have a good root system that will help them stand the shock of transplanting.