In Pursuit of Variegated Roof Iris

  by Bob Pries

Iris tectorum alba, Pries photo

Iris tectorum (the Japanese roof Iris) is one of the easiest species to grow. Many years ago, I heard about a variegated form and got very excited. In my eyes, the white flowers of Iris tectorum are one of the most enchanting of Iris flowers. Unfortunately, this variegated form was said to have blue flowers. I imagined how stunning the white flowers could be with beautiful variegated foliage.

When I finally saw some plants of this variegated form, I was somewhat disappointed in the quality of the variegation. It was much like some of the variegated, tall-bearded irises that have irregular streaks and stripes. It was, though, much more pronounced than what you see in virus-infected plants. However, the plants themselves were not robust growers, and this clone seems to have died out in cultivation.

There was one troubling fact. The insert image of the blue flowers was not Iris tectorum. At the time, I lived in zone 6 in Missouri. The image I thought looked very much like images I had seen of Iris japonica. But japonica does not tolerate zone 5 winters well. The foliage when received appeared more glossy.

Iris japonica flowers, Hensler photo

 

About the same time that I was eagerly searching for someone who could share a piece, I saw an advertisement in a general garden catalog. It showed an image of beautifully variegated foliage and a small insert of blue flowers. It proclaimed, "Variegated Iris tectorum for sale," so of course I ordered it. But the leaves were more slender than I. tectorum and it appeared I had gained a new house plant.

Variegated Iris japonica Pries photo

In trying to find out more about variegated Iris japonica, I found references that suggested there is more than one form of variegation and at least two types grow in Japan.

The next year I visited a very large perennial nursery outside of St. Louis. The proprietor—who I knew well—was proud to show me a huge planting of variegated Iris tectorum being used as a groundcover. It was absolutely gorgeous. I felt a bit guilty when I told him it was not Iris tectorum but japonica. I warned him it would not make it through the winter but he did not dig it up and it all perished. More and more I kept seeing Iris japonica incorrectly labeled as Iris tectorum in the trade.

Iris japonica, one of three focal points. The others are Brugmansia 'Snowdrift' upper right and variegated Curcuma; Pries photo

Since moving to North Carolina (zone 7) I have grown many forms of Iris japonica. Tony Avent’s Plant Delights Nursery (zone 8) has selected several with differing flower colors. All the green leaf forms survive my winters. They are especially good as groundcovers under the dry shade of Pine trees. But I still love the variegated form which I maintain as a pot plant. It seems just a bit more tender than its green cousin. It is especially attractive as a focal point in my houseplant garden and is a feature of my deck garden of potted plants. I would be delighted to find other forms of the japonica but someday I hope to grow a true variegated tectorum.

Variegated Iris japonica repeats the angular texture of Yucca 'Colorguard' Pries photo

What is in a name? Lophiris - Crested Iris – Part One

By Maggie Asplet

When thinking about what I would write for this blog, it was before our main spring bloom season, just at a time when the sight of things to come was teasing us.  Many of our New Zealand iris lovers have these beautiful irises in their garden.  I am talking about the “butterfly iris” or more correctly Iris japonica and some of the different hybrids.

This iris is a native of China and Japan, a species in the genus Iris, it is also in the subgenus of Limniris and in the Lophiris section.  It is a rhizomatous perennial plant, with pale blue, lavender or white flowers with an orange or yellow crest. It is cultivated as an ornamental plant in temperate regions.

Often referred to as either a Crested Iris or an Evansia, and then there is Iris confusa. Confused, I sure am.  I quite like the term “butterfly iris” and look forward to any discussion relating to the correct naming.  This is one section of the iris world that I need to learn more about.

Iris confusa (?) in my garden

Actually, as I started my research on these irises, I was rather surprised to fine how many I have, so more research and understanding is required. 

The next one is a delightful clump of Iris confusa ‘Martyn Rix’, in my garden

Named for a UK plants man Martyn Rix, this iris gets bamboo-like stems to 2'-3' (80 – 95 cm) topped by fans of long green leaves from which the long flower stems emerge bearing a swarm of dark blue-violet flowers which are deeper coloured than typical for the species.

Another similar iris known as ‘Chengdu’, is often confused for the above iris.  Similar in size but slightly different in depth of colour.  Registered by Jean Witt in 1997, this Evansia SPEC grows to around 24” (61 cm).  Standards and style arms are light lavender, the falls slightly darker, signal white with medium lavender halo and a yellow crest.  Originally collected in 1980 by Jeanne Gardiner between Kanding, Tibet and Yaan, Sichuan, China around 3000’ elevation.

‘Chengdu’ in my garden, which was flowering in late September

Now to look at some of the hybrids created in New Zealand

Queen’s Grace, growing in my garden

Queen’s Grace is a cross between I. wattii X I. tectorum hybridized by Jean Stevens in 1955.  36" (91 cm), standards are clear lavender-blue, the falls same flecked deeper at haft; multi-ridges crest on falls, cream-white flecked brown.

We still have a number of gardens where it is blooming in New Zealand.

Question Mark

Registered in 1982 by Revie Harvey, this Evansia grown to 54-60” (137-152cm).  Smooth pale lilac, deeper toned fleck markings, bright gold crests, signal points radiate from crests, dark green foliage topping dark purple green canes.  It is of unknown parentage but probably I. wattii X Darjrrling or I. Confusa

Kilkivan

Registered by Mrs M Harvey in 1982, this Evansia grows to 54-60” (137-152 cm).  It is pale lavender with pale gold crest on white zone, numerous deep lavender signal markings, pale lavender style arms with fringed tips; deep green foliage topping medium green canes.  Parentage is an Ellis white sdlg. X Question Mark.

In Part Two we will continue to look at what I have growing in my garden, and others from around the country.