Thursday, April 4, 2013

Iris Evansia, Crested Iris, CHENGDU.

The Evansia or Crested Irises are a interesting group of different irises all with different chromosome counts. 'We at home' are just starting a collection of these plants now that the trees we planted some 18 years ago are starting to give the mottled shade habitat that evansias like so much to grow in. Evansias do like growing in many places in New Zealand and these delightful and distinctive irises add great value to the garden, although they are not used as much in gardens as they deserve to be. 
 Much has been said and written about the 'DNA' of 'Chengdu', some have suggest it is a natural form of I.confusa and other more enlightened folk have suggested it is a species of its own. What we do know for sure that it was collected in Sichuan, South West China by Jean Gardiner and sent to Jean Witt in America. It forms a dense clump of glossy rich green leaves that are held in fans, bottom of this foliage strongly tinted purple-black, Historic Iris aficionados refer to this as PBF. The branching bloom stalks rise to a height of 102cm (42"). Blooms for several months in Spring with exquisite almost orchid-like 4-4.5cm blooms in contrasting shades of deep lavender that have a bright yellow crest surrounded with white which in turn is surrounded with a prominent purple zone which extends as veins towards the blade of the fall. Slight vanilla fragrance.
The Iris Yearbook (BIS), 1991,  “Evansia Irises : Two New Species”,  page 96, Dr. Jack R. Ellis.
The second potential new species I. "wittii", is named (without permission) after Mrs Jean Witt of Seattle who kindly sent a plant approximately ten years ago, with details of its origin/location in south west China. It was received as a probable form of I. confusa. With smaller growth form, more delicate inflorescence and with mid violet-purple flowers, it is morphologically quite distinct from all previously introduced forms of I.confusa. It has recently been cytologically studied by Young Lim, who has noted chromosomal differences from I."confusa', I. "wattii" and I. "nova". The cytogenetic evidence combined with the morphological differences would justify its recognition as a different species in the cane bearing Evansias assigned to group 1.

Gardening with Iris Species, Proceedings of an International Symposium, Edited by James W. Waddick, 1995.
'Following the Evansia Trail, From a Question Mark', Revie Harvey, New Zealand.
The latest edition to our Evansia collections has not to our knowledge been given an official title. It is very popular with all growers and viewers and is commonly called "Chengdu" in honour of the district in China from whence it was discovered in recent days. In this Southern Hemisphere, it has adapted well to seasonal climatic conditions. The bright green foliage is attractive in the off-season. The florets are small but neatly proportioned in mid-violet-blue and by far the most colourful of the range. For a period there was a theory that it was another form of I. confusa, a view that I refuse to accept and I felt was proven when I grew the two plants in close proximity. Like all Evansia forms brought into cultivation from the wild, it is a reluctant pod parent. However seedlings raised from a bee pod have been true to the blue parent. At this time the first blooms are being from a cross of "Kilkivan" with 'Chengdu" showing some variance from both of the parents.

Irises, A New Zealand Gardener's Guide, Pamela McGeorge and Alison Nicoll, 2001.
Evansia or Crested Irises
Two evansias more recently available are I.'Nova' and I. 'Chengdu'. The first of these two is a tall plant that sets seed reliably and has large white blooms marked with gold. It was found in a garden in the U.K., but has not yet been found in the wild. I. 'Chengdu', however, came from China, and it appears from a recent study that it might be a species in its own right. It has glossy dark green leaves and deep lavender flowers with a prominent purple zone surrounding the white area adjacent to the the deep yellow crest. Its growth habit is similar to I. confusa and is very similar to a variety named 'Martyn Rix'.

AIS Checklist 199
CHENGDU (Jean Witt, R. 1997). SPEC (evansia), 20-24" (51-61 cm), M. S. and style arms light lavender; F. slightly darker, signal white with medium lavender halo, yellow crest. Collected 1980 by Jeanne Gardiner between Kanding, Tibet, and Yaan, Sichuan, China, ca. 3000' elevation; probably I. confusa.


As always clicking on the above image will take you to the larger, higher resolution version.
Photo credit and copyright Iris Hunter.


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