This section is from the book "The Gardener's Monthly And Horticulturist V26", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
"M. L. H.," Minneapolis, Minn., asks: " Will you kindly tell me what causes rose leaves to turn black, like the enclosed, and what I can do to prevent them from doing so? My bushes are thrifty, and appear healthy, but the leaves turn black, and then drop off, and I should like to know the cause. I have no trouble wintering roses here, where it is no unusual thing for the thermometer to show 400 below zero. Last winter my tea roses came through all right out of doors.
"Perhaps it will do no harm to say that I am much pleased with The Gardeners' Monthly and Horticulturist".
[This is one of the numerous species of fungus parasites that feed on healthy vegetation. Some feed on the external surface, and are readily destroyed by sulphur. Others, and yours is of this class, work in the tissue under the skin, and sulphur cannot reach them. Nothing has proved effective. But there is this comfort, that this class is not regular in its appearance. You may not have it next season. - Ed. G. M].