JARS v50n4 - Red Lepidotes

Red Lepidotes
Pat Halligan
Freeland, Washington

Back about 15 years ago I started a breeding program to produce red lepidotes. I assembled the reddest lepidotes I could find, including Rhododendron calostrotum 'Gigha', several forms of R. campylogynum , a bunch of R. racemosum , a few types of R. keiskei , R. spinuliferum , a couple of R. edgeworthii , a dump truck full of various and sundry hybrids, and a partridge in a pear tree.

My first hybrids were very exciting. Some produced red leaves, which were truly astounding to me. Wow! Just think how great it would be to have bright red-leafed rhodies all lined up in a row at the local nursery. Of course, all those red-leafed plants turned nice and green as they got older. Drat! I learned that having red leaves was a juvenile characteristic of many rhodies.

The flowers were also just as exciting - pretty little light pink flowers with red tips, and some of the late bloomers were red all over. And face it, 63A "Spiraea Red" 1 is quite a nice red for a lepidote. (The numbers refer to the Royal Horticultural Society color chart, which is used in the registrations listed in the ARS Journal.)

Determined to press on, I truly found out the joy of R. spinuliferum . It's a weed in the wild, and bred even to R. keiskei 'Yaku Fairy' it unfailingly produces a weedy looking hybrid. To add to the joy, its weedy habit breeds true to form generation after generation, prompting hybridizer Frank Fujioka to refer to my hybrid growing area as my "weed patch." I love my little weeds, as only a father could.

Further breeding brought down my best color to 53A "Cardinal Red," 1 although most were in the 54 "Spinel Red" 1 to 63 range. One plant had flowers somewhere between 47A "Currant Red" 1 and 53C depending on how you squinted your eyes. Unfortunately, harsh winters took their toll, and at times my garden looked like Flanders Fields. I ran out of little crosses to mark my plants' graves, so I decided to simply press ahead...to produce new soldiers to replace those fallen in battle with the elements.

[(R. keiskei x R. spinuliferum)
x 'Firecracker Tori']
Red hybrid lepidote [( R. keiskei x R. spinuliferum) x 'Firecracker
Tori'] compared to an apple. This photo was taken with a flash,
which helps avoid false colors. Note that the inside of the flower is
a lighter color (43D-48C)than the outside(46A-47A). The
inside color darkens with time in response to light.
Photo by Pat Halligan

Slowly, more and more plants appeared with flowers in the 47 to 53 range, and eventually I got one plant to come up with some smallish 46A "Currant Red" 1 bells. Finally! I had gotten a truly red lepidote. Unfortunately, the plant looked like it needed some Roundup to make way for redheads with shapelier figures. Being partial to dowdy looking plants, I immediately used it as a parent, and it rewarded me by producing some of my worst plants.

Actually, I use every acceptable plant as a parent, rather than selecting the very best and using it alone. I call it "population breeding" and use it to ensure that unseen genetic material is not lost. Which brings me to my next point.

In my most recent generation I am now getting 46's and 47's routinely, but a select few plants are now showing colors as orange as 44 "Scarlet." 1 All of these orange-red plants came from parents with unpromising looking flowers, many of which have long been discarded. Had I limited my breeding to only the very best plants, I would not have obtained such orange colors.

Several years ago, choosing a color was easy. One plant had purpley flowers and the other was red - no brainier. Now, though, things are tougher. What with all those 44's through 47's coming in all shades of intensity and nuances of one sort or another. It used to be I could just set my plants out in the room where I breed them and compare the colors. Now, under the incandescent lights, all the flowers look the same.

What was worse, I found I was even having difficulty in full sunlight. A flower that looked great in full sunlight now looked lousy in the shade. What was even worse, when I brought a truss into a meeting, it always looked awful. The fluorescent light brought out all the blue the flowers could muster, while dulling any red that was present.

Amazingly, differences in color that jumped out at me under fluorescent lighting just melted into bland sameness when I took the plants over to the incandescent lights. In the shade on a sunny day, those glaring differences were reduced to mere nuances. And in the sun, everything was so bright, red was red, no matter what.

I had to think about it for awhile. (I'm a slow thinker. ..probably not a bad trait for a hybridizer, where events are measured in decades.) Then the bright idea. Gee, if fluorescent light is so good at bringing out all the bad colors, why not use it to screen plants for parents. And so I did.

{[(R. campylogynum x
R. spinuliferum) x near sibling 'Firecracker Denisia'] x 'Firecracker Tori'}
Dark red hybrid lepidote {[( R. campylogynum x R. spinuliferum )
x near sibling 'Firecracker Denisia'] x 'Firecracker Tori'}. This was
taken with a flash, which causes a black background. This
flower is the same color (46A) inside and out.
Photo by Pat Halligan

A few hybrids show virtually no change in color under fluorescent lighting, indicating a lack of muddying bluish pigments. One plant has nicely shaped flowers of 45A even under fluorescent lights, suggesting that better things are yet to come. Although these plants lack intensity of color on the inside of the corolla, I'm hoping that future generations will see really bright red lepidotes. This spring will probably see the first flowers of the progeny of the plants in the photos. I'll keep you posted.

Pat Halligan, a member of the Whidbey Island Chapter, authored the articles on Garden Gems that have run in recent issues of the Journal.

1 The Universal Color Language describes (63A) as "strong purplish red"; (54's) as "strong purplish red," "deep purplish pink," "strong pink," "moderate purplish pink"; (47A) "moderate red"; (44s)"vivid red," "vivid reddish orange," "deep yellowish pink".

The Royal Horticultural Society Colour Chart

Rhodoholics everywhere depend on the RHS Colour Chart to describe flower color. If you breed rhodies, this chart soon becomes an indispensable tool. It is much more accurate than photos, which are notoriously unreliable. A good companion to the chart is A Contribution Toward Standardization of Color Names in Horticulture . This little book compares the various color systems and explains a lot of the mystery surrounding color.

Each color has three qualities: hue, brightness and saturation. Hue is the type of color, e.g., green, red. Brightness describes the amount of light reflected by the color, e.g., dark blue, pale blue. Saturation is the purity of the color, e.g., sky blue, steel blue.

Saturation, or purity, is the hardest concept to grasp. The colors of the spectrum are all pure colors. When you mix one color with another, or with white or black, you decrease the saturation, or dull the color. These are called "greyed" colors.

The RHS Colour Chart is arranged into four fans. The first fan covers yellow, orange and red (numbers 1-56). The second fan continues the journey through the purples, violets and blues (numbers 57-110). And the third fan completes the trip through the blue-greens, greens and yellow green (numbers 111-154) bringing us right back to the beginning. The fourth fan presents the greyed colors (you know, the ones your interior decorator picked to match your Toyota.)

Each color card has four shades of the same color, arranged from dark to light (A to D). One card may be quite dark while the next one is light, so you must refer to the chart to know whether a color is light or dark. Here's an example of two colors compared: 45C vs. 56A. The first color is quite a pure red of vivid brightness, while the second color is rather pale and blued. Are you confused? I have a solution: buy an RHS Colour Chart and everything will become crystal clear.

To compare flower color with the chart, select a spot with "north light." This will be out of the direct sunlight but in a bright area exposed to a wide expanse of sky. Proper light is absolutely essential to get an accurate color. For example, one of my plants has flowers at 45A in daylight, but 46B-47A in fluorescent light. Incandescent light or daylight near sunset makes colors more orange. Direct sunlight is too intense and saturates the eye, making subtle comparisons impossible.

Hold the petal next to the color strip or under the hole provided in the middle of each strip. Compare the colors in front of a uniform background. Be sure to look away from the flowers regularly at something of an opposite color. Once your eyes become fatigued, you will not be able to discern subtle color differences.

The color charts are not perfect. Many colors are missing, and you will just have to use the nearest approximation. The fiery color of Crocosmia 'Lucifer' is so brilliant and saturated that the color chart can only give a pale approximation. If I could only have such a problem with my hybrids.


1.  R.H.S. Colour Chart. The Royal Horticultural Society, London, 1966, 1986, 1995. The R.H.S. Colour Chart can be ordered from RHS Enterprises Limited, RHS Garden, Wisley, Woking, Surrey GU23 6QB, England for £70 plus shipping.

2.  Huse, R.D.; Kelly, K.L.; ed. Voss, D.H. A contribution toward standardization of color names in horticulture. American Rhododendron Society; 1984.