Fifth Generation Glass White was in Sid Burns’ garden in 1965 and I don’t remember anything about it except it was white (I don’t remember anything about a blotch) and that Sid and Paul Vossburg valued it greatly. Paul developed it by first selfing ‘Glass White’. Only 3 or 4 seedlings of that were white, the rest mauve. He then crossed the two whitest, grew the seed and repeated the crossing of the two whitest. It took five generations until all the seedlings came white.
It was VERY DIFFICULT to root, in fact I don’t think either Paul or Sid was able to root it. It and ‘La Bar’s White’ gave white catawbienses the reputation of being impossible to root. I think Russell Harmon layered La Bar’s White to propagate it. I remember driving to the La Bar Nursery in Stroudsburg, Pa to pick up some plants for the NY ARS booth at the International Flower Show in New York City in 1966 or 67 and Russell have me two small plants of La Bar’s white as a VERY SPECIAL FAVOR for Sid and Planting Fields. They were very hard to acquire. Someone was tissue culturing it several years back and I got a couple, but it is not worth growing as it is hopelessly leggy.
I think for us on Long Island the days of using catawbiense in hybridizing are long gone. Mr Dexter killed the idea of using catawbiense on Long Island and coastal New England with his spectacular fortunei hybrids. I think the Fifth Generation Glass White is long gone.