Degeneration, Vegetative Degeneration, Deterioration

[From A Family of Roses, by Sam McGredy and Sean Jennett, pp. 21-2:] the clone of millions of plants throughout the world represents millions of buds taken from the original plant or from other plants that have been budded from the original one. In time a deterioration sets in, and the variety has to be withdrawn from the market. That period is not by any means the same for each rose. The rose 'Mrs. Sam McGredy' has been going strong for forty years, 'Peace' itself is still vigorous after more than thirty years [Note: this book was published in 1971], and some roses, such as 'Madame Caroline Testout', raised by Pernet-Ducher in 1890, have been on the market for eighty years or more. Many modern varieties, more interbred and more distant from the wild species, keep their vigour for a much shorter time...

[From Those That Fell by the Wayside, by W. Slinger, p. 92: the author was writing about how some roses deteriorate with age...] Why is it I cannot grow 'Mrs. John Laing' as I grew it 50 years ago? Yes, 50 years ago I could cut 100 perfect blooms from 100 plants; today I cannot cut even one flower that would bear comparison. With monotonous regularity, 'Mrs. John Laing' won medals as the premier bloom at shows...

[Ibid, p. 93:] 'La France', introduced in 1867 and supposedly the first hybrid tea, is still comparatively popular [in 1950]. It used to grow like a weed and produce blooms in greater abundance than any other variety. I must confess, it now looks very weary beside the newer varieties... 'Marechal Niel' is another grand old rose that has lost much of its nineteenth century glamor. Introduced in 1864, it was one of the leading roses under glass for 50 years...