JARS v55n4 - Rhododendron 'Marcia Ann', Grandchild of the ARS Seed Exchange

Rhododendron 'Marcia Ann', Grandchild of the ARS Seed Exchange
Pat Halligan
Freeland, Washington

Almost twenty years ago, I ordered a bunch of seed from the ARS Seed Exchange. One of the seed lots was a cross of ( Rhododendron lindleyi x R. nuttallii ), selfed (1981 lot #898) by H. J. Braafladt of Eureka, California; and another was R. edgeworthii , selfed (1981 lot #513) by Ron C. Gordon of New Zealand. I did not expect to produce any "finished" plants from these seeds. Rather, I was looking for "lead-in" plants to introduce fragrance and large flowers into hardy lepidote breeding lines.

Surprisingly, the R. lindleyi x R. nuttallii cross produced quite a variety of very nice plants, producing flowers with quite a variety of shapes, sizes and types of fragrance. One plant even won Best of Show at the 1985 ARS Annual Convention in Seattle. This was the plant that I used to make the cross that resulted in 'Marcia Ann'.

The other seed lot produced only one seedling, clearly a form of Rhododendron edgeworthii , with very wide spreading flowers of average size, with large red calyces, but only slight fragrance. The main feature of the plant was its foliage, with shiny flat bullate leaves, nice indumentum, and a very good branching habit, much better than would be expected of this species.

I crossed these two parents in 1988 and came up with a number of seedlings, which I planted outdoors when they were a few months old. Only one plant survived the winters, which was fine with me, since I was looking for plants that have at least some hardiness to use as parents.

The original plant eventually died, but I managed to root the branches, and before long I had several plants growing. I was amazed by its flowers and leaves, which seemed to combine the best features of both parents. It had inherited much of the size and fragrance of Rhododendron nuttallii but with the wide spreading petals and large red calyces of R. edgeworthii . Its leaves were an extra-large version of the flat rigid bullate edgeworthii leaves, and its habit reflected the highly branched edgeworthii parent. Unlike either parent, it had a tendency to set multiple buds.

It was almost too good to be true. I gave a plant to Paul Molinari of Occidental, California, to evaluate, because I thought it might make a good plant for California. This last year, Paul surprised me by saying that he was propagating the plant for commercial production. He found that the plant was quite compact and free flowering and that it would make a good commercial plant in California.

So what's the point? This plant was hardly a result of any great plan on my part. It was a lucky byproduct of a breeding program which has entirely different goals, a result of two parents that came from the Seed Exchange. The point is that the Seed Exchange is absolutely crammed with great crosses and species seed.

I have a feeling that most breeders prefer to use their own crosses to produce hybrids, and I can see why, since most breeders like to see their own name attached to their plants. But even so, you can see from my example that Seed Exchange plants can make excellent parents.

I would also like to emphasize that a plant that came out of the Seed Exchange won Best in Show at the 1985 ARS Annual Convention. This plant competed with a great number of plants produced by well-known breeders, numerous old standards and, of course, many of the newest and hottest plants.

And there was another bonus that I got from the Seed Exchange. I have had a very difficult time crossing plants of the Megacalyx series* with hardy lepidotes. I tried all sorts of species and hybrids, but to no avail. I made the cross that resulted in 'Marcia Ann' as an attempt to bridge the gap between the Megacalyx series and hardy lepidotes with the species Rhododendron edgeworthii . Surprisingly, this hybrid has produced viable seedlings when crossed onto R. racemosum x R. edgeworthii . Then another surprise. One of the seedlings of R. lindleyi x R. nuttallii F2 also produced viable seedling when crossed onto R. racemosum x R. edgeworthii . Thanks to the Seed Exchange, someday I may have the fragrance and flower size of the Megacalyx series bred into hardy lines.

Those of you who read my article "Incest Among Plants" in the winter 2000 issue of the Journal will remember that I said that good plants don't come from selfing. Well, there are always exceptions, and Braafladt's cross was definitely an exception to that rule. 'Marcia Ann' serves to show that selfed plants often make very good parents when out crossed.

Now for your assignment: Order seed from the Seed Exchange, grow the plants, and make some crosses using the seed exchange plants. You'll be pleasantly surprised by how good some of the Seed Exchange crosses are. Many of them come from the very best hybridizers and represent some of the most advanced thinking among hybridizers. Take advantage of their expertise, and you won't be sorry.

* Under the Sleumer and Edinburgh revision of the classification of the genus Rhododendron , the Megacalyx series was placed in subsection Maddenia . In the Encyclopedia of Rhododendron Species , authors Peter and Kenneth Cox have subdivided the subsection into four groups, one of which is Megacalyx. The species R. megacalyx is the sole member of this group.

Pat Halligan, a member of the Whidbey Island Chapter, has contributed articles to the Journal on results at the Meerkerk Rhododendron Gardens Hybrid Test Garden and on his own hybridizing program.