Evansia Or Crested Irises

Those gardeners who have always thought of irises as tall, stately, richly hued plants may be surprised to discover the Evansia or Crested irises. For the group includes the smallest iris there is - a miniature whose flowers appear on stems mere inches above the ground. Others of the group form spreading evergreen clumps that look comfortable in a shrubbery and have orchid-like flowers produced on long springy stems. In spring they are starred with dozens of dainty flowers delicately frilled, their markings subtle. It is hard to imagine the relationship between these plants and the formal, highly bred bearded irises.

The distinguishing feature of all these irises (except one hard-to-find species) is the serrated, or toothed, crest on the haft of the fall where you find the beard on the bearded iris and the signal on Siberian irises, Louisiana irises or other beardless varieties. The crest may look rather like the cockscomb on a rooster (though not bright red), or it may be merely the suggestion of a raised furry patch, similar to those seen on Dutch or Spanish irises. It is usually a distinctive color or pattern.

Variable in size and height, they fall into two distinct groups: those that are dormant in winter and come mainly from North America, and the others, which are tender, sub-tropical, evergreen and native to Asia.

Why Evansia irises? As with so many plants, the name comes from the person who introduced them to the western world. All we know about him is his name and the fact that he worked for an English company in India. Thomas Evans was responsible for introducing I. japonica to England in 1794 and his name lives on. Contrary to most irises, the Evansia irises (or orchid irises as they are sometimes known), will usually perform best in light shade. Hot sun or frost may burn the very broad, flat, strap-shaped leaves that many Evansia irises have and that add to their attraction.

Evergreen group

In mild temperate climates, the evergreen Evansia irises are attractive, useful landscaping plants that look good even when they are not in flower. These irises form clumps of distinctive foliage that add interest to the edges of woodland plantings where overhanging trees will protect them from frost and excessive hot sunshine.

In warmer areas, these irises continue their growth nearly all year with very little dormancy in frost-free situations. Where winters are too cold for them to survive unprotected, they can be grown in containers, and then moved to shelter before the killer frosts arrive. They generally need no more care than the annual application of an all-purpose fertilizer and a protective sprinkling of snail bait around them in spring.

Species

I. japonica

This iris is a native of China, where it grows as far west as Sichuan, flowering through April and May on grassy or rocky slopes in woodland and among rocks beside streams. It was given its misleading name after it became widely naturalized in Japan, originally arriving in that country as a gift from the Chinese Emperor to his Japanese counterpart.
Dense clumps grow to 2 ft (60 cm) in height, with the flower spikes emerging above the leaves. The joy of this plant is its multi-branched spikes, each bearing many flowers over a period of five weeks, although flowering can be negatively affected by an exceptionally cold winter.
It will grow in full sun where there is no risk of frost, but expect the leaves to lose a lot of their gloss and become almost yellowish green; the flowers will be paler.
The plant has slender, creeping rhizomes and where it's not checked by severe frosts or drought, it will grow vigorously and increase quickly.
It delights in moist, rich, slightly acidic, loose, composty soil; this iris likes to be fed frequently -rotted manure is good -and needs to be well-drained. A shallow-rooting plant, divisions can be pulled away by hand from the main clump for replanting. This can be done successfully at any time of the year, though late spring is best.
If you live in a climate with no more than slight frosts and have a steep bank you want to keep free from intruders (or weeds) you might try growing I. japonica.
There is a form bearing beautiful white flowers subtly marked in yellow and with deeply fringed ends on its style arms called I. japonica forma pallescens.

I. wattii

This iris is a native of Yunnan province in China. It is the tallest of the Evansia irises, with luxuriant foliage that develops as leaf fans growing from bamboo-like stems, reaching more than 5 ft (1.6 m) in height. Some growers recommend staking the flowering stems as they emerge at the first hint of spring, to keep the clump in shape and to prevent them from bending over with their own weight -under- standable when you realize that the flowering spray can be 6 ft (2 m) tall. Each spray is branched and may produce up to 50 flowers during an eight- to 10-week period. With delicate, clear lavender flowers that are ruffled, frilled and almost 4 in (10 cm) across, a bush in bloom can be a spectacular sight.
This is not a plant to grow in windy, exposed areas for the flowers damage easily, as does the foliage, but it will sustain light frosts without harm.
Like I. japonica, it increases rapidly but remains tidier in shape. Divisions can be taken from the tough, side rhizomes at any time of the year. They lift out with roots intact, ready for planting. Propagation is also possible by taking cuttings from the stems. To do this, place pieces in water for a couple of weeks and new roots will appear from joints in the canes. The plant is not always long-lived, so it's a good idea to start new plants from time to time.

I. confusa

This iris is another of the Evansia irises with dainty orchid-like blooms. Originally confused with I. wattii when it was first introduced to England - hence the name -it is similar but does not grow as tall and the flowers, normally white with yellow and purple dots on the falls, are smaller. Another native of Yunnan, where it grows on steep slopes among rocks and scrub, it flowers in May and is hardy if given some shelter.

I. tectorum

This iris is another Evansia originating in China and the Himalayas, its flower differs from the preceding species, with a form less like an orchid and more reminiscent of the flat Japanese irises. It's a large bloom, about 4 in (10 cm) in diameter, soft blue-mauve with a prominent, white, toothed crest and standards that are only slightly elevated. Beautiful as the flower is, I. tectorum is best known for the traditional custom of planting it on roofs in Japan. Legend has it that Japanese women used to grind up the roots of the rhizome to make a face powder. When famine struck and they were forbidden to grow any plant in the fields that wasn't food, they planted the rhizomes in the roof thatch rather than go without their precious face powder.
In its native habitat I. tectorum enjoys dry cold winters and warm wet summers. A lower-growing species, it will stand more sun and much colder winters than the preceding Evansia irises, going almost dormant in cold climates. As you would expect with a plant that flourishes on roofs and walls, it likes perfect drainage and full sun. The roots are very shallow and, where happy, it increases fast, so divide it up every two or three years, give it a meal of sheep manure or enriched compost, and the plant will stay vigorous. Grown among stones it will probably need new soil added each year. It can be divided up as soon as spring flowering is over or, alternatively, as soon as the rains start in fall. Although generally frost hardy, young spring growth will be damaged by frost. There is also a white form of I. tectorum that comes true from seed.

I. milesii

This iris comes from the same regions as I. tectorum and grows up to 30 in (75 cm) tall. It favors similar soil conditions although it does not tolerate lime. It forms an attractive, vigorous clump of foliage, much more upright than I. japonica though the flowers, which appear in early summer, are more slender. Light pinkish purple in color and with more erect standards than in other Evansia irises, flowers appear on slender branched stems good for picking. This iris is dormant in winter, with all the foliage disappearing to leave the rhizomes lying on the surface of the soil, noticeable for their bright green color.