The sweet briers, Austrian and rugosas may be kept in bush form; but the trunks may be cut out at the ground every two or three years, new shoots having been allowed to come up in the meantime. All rampant growths should be cut back or taken out.
Insects and diseases of roses.
Most of the summer insects that trouble the rose are best treated by a forceful spray of clear water. This should be done early in the day and again at evening. Those having city water or good spray pumps will find this an easy method of keeping rose pests in check. Those without these facilities may use whale-oil soap, fir-tree oil, good soap suds, the tobacco preparations, or Persian insect powder.
The rose-bug or chafer should be hand-picked or knocked off early in the morning into a pan of coal oil. The leaf-roller must be crushed.
The mildews are controlled by the various sulfur sprays.
Winter protection of roses.
All garden roses should be well mulched with leaves or coarse manure in the fall. Mounding earth about the root also affords excellent protection. Bending over the tops and covering with grass or evergreen boughs is also to be recommended for such kinds as are suspected to be injured by winter; the boughs are preferable because they do not attract mice.
North of the Ohio River all the everblooming roses, even if they will endure the winter unprotected, will be better for protection. This may be slight southward, but should be thorough northward. The soil, location, and surroundings often determine the extent of protection. If the situation is not so favorable, more protection will be necessary. Along the Ohio, a heap of stable manure, or light soil that does not become packed and water-logged, placed about the base of the plants, will carry over many of the tea roses. The tops are killed back; but the plants sprout from the base of the old branches in the spring. Bon Silene, Etoile de Lyon, Perle des Jardins, Mme. Camille, and others are readily wintered there in this way.
About Chicago (American Florist, x., No. 358, p. 929, 1895) beds have been successfully protected by bending down the tops, fastening them, and then placing over and among the plants a layer of dead leaves to the depth of a foot. The leaves must be dry, and the soil also, before applying them; this is very essential. After the leaves, a layer of lawn-clippings, highest at the middle, and 4 or 5 inches thick, placed over the leaves, holds them in place and sheds water. This protection carries over the hardiest sorts of everblooming roses, including the teas. The tops are killed back when not bent down, but this protection saves the roots and crowns; when bent down, the tops went through without damage. Even the climbing rose Gloire de Dijon was carried through the winter of 1894-1895 at Chicago without the slightest injury to the branches.
Strong plants of the everblooming or hybrid tea roses can now be had at very reasonable rates, and rather than go to the trouble of protecting them in the fall, many persons buy such as they need for bedding purposes each spring. If the soil of the beds is well enriched, the plants make a rapid and luxuriant growth, blooming freely throughout the summer.