I have three very distinct forms of the Mt Omei balsam in my garden, two planted out and one still in a pot. The one that I have had the longest is the form most often encountered here and came to the UK from America, having been introduced to cultivation by Don Jacobs of Eco Gardens Nursery. It is most often referred to here simply as Impatiens omeiana, with no clonal name, but perhaps should be called I. omeiana ‘Eco Hardy’. The online RHS Plantfinder lists eight varieties but does not list this clone so it has to be assumed that it is what you are getting from the 21 listed suppliers of Impatiens omeiana.
I have it growing in two places, one in moist soil shaded by the taller Astilbes amongst which it grows, the other, in the picture above, a shady corner beneath an assortment of other plants. The picture shows it flowering a year ago: this year it collapsed in the hot dry summer and has gone completely dormant. I would expect it to come back up in the spring, but it clearly needs to be in ground that never dries out. The clump amonst the
Astilbes suffered some leaf scorch but is now flowering well as in this picture.
The second clone I obtained with a label saying Impatiens aff. omeiana, implying that the seller didn’t know what it was but was having a stab at I. omeiana. I am now fairly certain that it is the form now called ‘Pink Nerves’. It has vivid carmine red midribs and veins to the leaves which also have a dark red reverse. The insides of the flowers are
spotted red on a yellow ground. My confidence in my identification of it was shaken
when I saw what appeared to be the same thing at a plant sale labelled Impatiens omeiana ‘Chen Yi Red’. Chen Yi is a Chinese nursery with a dubious reputation for supplying illegally wild collected material, much of it wrongly named. Slightly surprising then that someone would be openly selling a plant in this country from such a source. I didn’t buy it and have subsequently learned that Chen Yi Red is probably the form that Nick Macer has given the clonal name ‘Sango’ to. Like ‘Pink Nerves’, it has a lot of red pigmentation but seems also to have a silvery marking either side of the mid rib, and slightly broader leaves, not that I have seen it in the flesh.
My third form is ‘Ice Storm’, introduced to the UK by Michael Wickenden from a Japanese nursery. That has light green leaves which are silvery on the top surface when they emerge in spring, though by mid summer they are mainly green.
The RHS online Plantfinder lists one or two others, though it seems likely there may be synonyms amongst them. A form collected by Dan Hinckley under collection number DJHC 98492 is not listed as such but may be the one listed as “long leaved”. One nursery is listed as having a variety called ‘High Voltage’ which looks attractive if not highly distinctive in pictures I have seen.
Given reliable moisture and shade, these are easy plants to grow, attractive in leaf and flowering in October when most other plants are shutting down. It will also make an excellent pot plant for shade. I won’t be chasing all round the country to get every form, but I’d buy others if I saw them.