JARS v63n4 - East x West - Intermediary Hybrids

East x West - Intermediary Hybrids
Jim Barlup
Bellevue, Washington

After I retired in 1995, I began to register the names of some of my rhododendron hybrids. In the spring of 1996 I received a phone call from Tony Knights, a member of the Massachusetts ARS Chapter. Tony had seen my name registrations in the ARS Journal and, intrigued by the descriptions and the parentage, he called me to inquire about the possibility of acquiring pollen. This was the beginning of a quest to combine the color saturation of Western rhododendrons with the hardiness of Eastern rhododendrons.

When I earlier decided in 1974 to landscape my yard, I wanted to do so with orange, peach, apricot and coral colored rhododendrons. After searching for them at local nurseries, it appeared that there were then very few in existence. The next logical step was to create them myself, so I began to learn about hybridizing and made my first cross in 1975. I was naive enough to think that if I just found the right combination of parents, I could achieve my goal. Little did I realize that I would have to create my own parent plants, sometimes taking several generations, to develop the right gene pool to meet my objectives. Developing intermediary hybrids was the key! Some of these intermediary plants were of value themselves, while some were just stepping-stones. I chose to register the names of those intermediary plants that I used extensively, whether or not they have commercial value, so that other hybridizers could track the parentage.

After years of trial and error, I was satisfied with the color, the shape of the truss and the foliage of some of my East x West crosses. I learned a lot from East Coast hybridizers who shared information, pollen and cuttings, and I acquired parent plants hardy to at least -26° C (-15° F), with some in the -29 to -32° C (-20° to -25° F) range. I succeeded in incorporating hardiness, but some desirable traits were still missing. Many plants were too large and took too long to bloom. Which parents would be able to produce compact offspring that bloomed at a young age? Over the years, experimentation with the East x West crosses provided me with the information I was looking for.

R. 'Sun High' R. 'Sun Blush'
'Sun High'.
Photo by Jim Barlup
'Sun Blush'.
Photo by Jim Barlup

A few of my East x West hybrids showed potential. 'Sun High' ('Mindy's Love' x 'Janet Blair') is a good medium yellow; 'Sun Blush' ('Scintillation' x 'Recital') has a pale yellow full truss; unnamed hybrids ('Coral Blossom' x 'Casanova') has coral orange tones and ('Cimarron Sun' x 'Big Deal') is a good yellow with a full truss.

R. 'Coral Blossom' x R. 'Casanova' R. 'Cimarron Sun' x R. 'Big Deal'
'Coral Blossom' x 'Casanova'.
Photo by Jim Barlup
'Cimarron Sun' x 'Big Deal'.
Photo by Jim Barlup

Since one of my goals is to create intermediary plants for further improvement by other hybridizers as well as myself, good fertility is also an essential trait. I estimate that 80% of my yellow, peach and coral hybrids have sterile pollen, but almost all of them can be used as seed parents. In most cases, 'Nancy Evans' and its offspring have sterile pollen, but there are breakthroughs! Allan and Shirley Anderson created a colorful cross of 'Nancy Evans' x 'Janet Blair' that has viable pollen, which has been registered as 'Sun Dust'. I have a few of my own offspring of 'Nancy Evans' also with viable pollen.

R. 'Christina Dee'
'Christina Dee'.
Photo by Jim Barlup

John Doppel, in the cold climate of Lenhartsville, PA, is presently testing about fifteen of my East x West crosses, with more being added each year. He gives me an ongoing report on their behavior: his evaluation of foliage, plant habit, condition of buds (from frozen to no bud damage) and helps me understand which hybrids are the best to continue working with. I found that using one hardy parent increases the hardiness factor, but the improvement is often not enough. Two years ago I began making crosses where three of the four parents had a hardiness factor of at least -26° C (-15° F), and preferably to -32° C (-25° F). John Doppel has created a new hybrid, 'Christina Dee' ('Wyandanch Pink' x 'Casanova'), with both its parents rated to -32° C (-25° F). 'Sun High' ('Mindy's Love' × 'Janet Blair') may be hardy to -13° C (-5° F) or lower, and I am hoping that my cross of ('Sun High' x 'Christina Dee'), hopefully a yellow, will be hardy to at least -26° C (-15° F).

R. 'Plum High'
'Plum High'.
Photo by Jim Barlup

There are other examples that demonstrate the utility of intermediary plants. Growers have expressed an interest in low growing purple elepidote rhododendrons, but the problem in creating them was that there were few plants with the desired traits to use as parents. The hybridizer must thus create them, and it seemed logical to cross R. degronianum ssp. yakushimanum with a purple or wine colored hybrid. In 1989, I crossed R. degronianum ssp. yakushimanum with 'Frank Galsworthy', which produced 'Frosted Plum'. I also crossed ('Fancy' x R. degronianum ssp. yakushimanum ) with 'Frank Galsworthy', which produced 'Plum High.' Both of these plants are low and spreading but the purple color was not dark enough. They needed more color saturation, but they were good steppingstones, indicating that I was on the right path.

R. 'Plum Passion'
'Plum Passion'.
Photo by Jim Barlup

I then crossed various purples with 'Plum High', such as 'Olin O. Dobbs', 'Purple Splendour' and 'Jonathan Shaw'. Of these, 'Jonathan Shaw' produced the best results. 'Plum Passion' ('Plum High' x 'Jonathan Shaw') had more desirable traits, as it is low growing (but not low enough), has good foliage and buds at a very young age. I then crossed 'Plum Passion' with a sister seedling, and in 2005, an offspring of this cross bloomed for the first time. It was 3.5 years old, 23 cm (9”) tall and 30 cm (12”) wide with three buds. It has 20 flowers in a dark purple ball truss and has good foliage and a reasonable amount of hardiness. 'Plum Passion' was hardy to -23° C (-10° F) and 'Jonathan Shaw' is reportedly hardy to -20° F, and these two parents may produce a plant that is hardy to -26° C (-15° F). This is what I had been looking for, and these plants were the breakthroughs I needed to continue on my journey, but they are still by no means the end. I believe that reaching my goal of creating hardier East x West hybrids and truly dwarf purples is now in sight. Time, patience and the cooperation of others who are passionate about rhododendrons is making this possible.

Jim Barlup
Jim Barlup is a member of the Cascade ARS Chapter.