I just happened upon this note, and wondered whether anyone had observed this in roses.
There seems to be a fascination with glossy leaves, and the erroneous assumption that shiny = fungus resistant. I once had a variety with very shiny leaves that suffered from mildew, rust and blackspot. Meanwhile, the downy-leaved Rosa moschata and fuzzy gray ‘Asta von Parpart’ are quite healthy. Of course, the San Jose Heritage garden is not the place to be learning about resistance to frost … or to blackspot.
The Garden 6: 89 (July 25, 1874)
Charles Elworthy
Nettlecomb, Taunton
Plums of most sorts, on open standards, are a good crop, in some instances weighing down the branches; I have noticed this season that the woolly and hairy-leaved kinds have resisted the frost better than the smooth and shining-leaved sorts.
This note does not deal with frost resistance, but confirms the general opinion that shiny leaves tend to resist at least some fungal attacks.
THE GARDENERS’ CHRONICLE. 24: 276) (Oct 8, 1898)
THE ORANGE-FUNGUS ON ROSES.
D. T. Fish
“Like “Wild Rose,” I have long known that the red-rust seldom or never attacks Teas, Hybrid Teas, Noisettes, Bourbons, Chinese, or Banksian, or smooth shining-leaved Roses. Even such Perpetuals as Boule de Neige, the Verdiers, and other more or less smooth and shining-leaved hybrid perpetuals escape the orange-fungus. Can it be that this pest cannot lay hold of or remain long enough upon the leaves to effect its reproduction? Suppose we try to starve out this fungus by offering it nothing to feed upon but smooth semi-shining varnished-leaved Roses.” http://bulbnrose.x10.mx/Roses/breeding/FishRoseRust1898.html