More on R. 'Lem's Cameo'
George W. Ring, Fairfax, Virginia
When the cross R. 'Dido' x 'Anna' came to my attention several years ago, I wondered if the order of listing the parents was correct since Mr. Lem had previously noted that R. 'Anna' had no pollen. In response to my question, Mr. Lem said that the cross was indeed listed correctly. It seems that he accidentally induced R. 'Anna' to produce pollen by green grafting a budded scion onto a R. ponticum hybrid and then enclosing the graft in a plastic bag. When the flower opened normally inside the bag the following spring it was loaded with pollen. This might be the source of the R. 'Anna' pollen used in the R. 'Lem's Cameo' cross.
Mr. Lem planned to repeat the graft to determine whether the pollen production was due to the R. ponticum under stock or to the additional moisture provided by the plastic bag enclosure. Perhaps someone having an R. 'Anna' could complete this study. At any rate, the method may prove to be useful for producing pollen from other reluctant clones.
An excerpt of Mr. Lem's March 19, 1969, letter giving the details follows. In this letter he also describes his success in getting R. 'Anna' to set seed. This was also an accidental discovery when he pollinated a truss as the spent flowers were dropping.
March 19, 1969
Dear Mr. Ring:
I just received your kind letter so will try to answer it right off.
First, Mr. Ring, you mustn't believe that I know how to force pollen and fertile seed from sterile rhododendrons. I have tried this as so many others have without luck. But this doesn't say it can never be done. Perhaps when these plants get old and well established they may someday start to give fertile seed and pollen. No my method is very simple, but I'm not yet for sure if it is the moisture which brings out the pollen or if it is the R. ponticum understock.
R. 'Anna' was the one I forced pollen from. We never saw it give any pollen out in the field, and everybody wished to cross with this one of the finest rhododendrons to use. I took a new started flower bud of R. 'Anna' and grafted on to a R. ponticum hybrid in August. Then put a plastic bag over it which was kept on all winter until the flowers started to open in the greenhouse in May. I expected it to bloom long before the field grown plants outside, but it did not. It shows it is not a forcing rhododendron. But when it opened its flowers and I removed the plastic, the pollen was already hanging an inch long from every flower in the large head.
It is my belief the moisture did it and not the R. ponticum understock. If so it should be well possible that you may force out pollen on any rhododendron in the field by keeping a plastic bag over it until the flowers open. But they shouldn't be planted in strong sun where they will burn inside the plastic.
When this above R. 'Anna' bloomed I crossed every flower and didn't get a single seed. So for many years we were all of the opinion there was nothing we could do with R. 'Anna' as a parent plant. But 3-4 years ago when I had quite a lot of R. 'Anna' in bloom outside and among them a bloomed out branch right in the trail, I grabbed some pollen from a very fine rhododendron and put it on the then bloomed out flowers of R. 'Anna'. At least many of the flowers had already fallen to the ground. A month later I could notice the seed pods swelling, everyone of them, and you should just be there and see what seed I got from it. The cleanest large seed you ever saw filled to the capacity. I have told a few friends about it and they had the same luck. I suppose some of these flowers of R. 'Anna' I put pollen on were two weeks old.
Now you are the first to know how I got the pollen from R. 'Anna'. But I feel sure many other rhododendrons can be improved the same way. R. 'Goldsworth Yellow' may be one. If it can be done with moisture, only, it is easy business. I will try it on R. 'Anna' in the field by Spring. So you tell Dr. Kehr no hormones or chemicals are used. I did use colchicine many years ago, but I never noticed any good results . . ."