Regional Growing Guide: New England
New England's erratic winter and spring temperatures, which might shift more than 50 degrees from one day to the next, can exact their toll on roses. Savvy gardeners winterize their plants by covering them with mulch, then wrapping them in woven mulch cloth or burlap to protect from both the cold and drying winds. The wraps come off in spring, and by June, the roses are in full bloom. Intense heat during July and August may slow down the plants, but they will bounce back with renewed vigor in September. Many of the most successful roses are new landscape roses and floribundas that are cold hardy and resist black spot and mildew.
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Choose Morning Sun for Roses
When selecting a site for a rose planting, choose a location in full sun, or one that gets at least 6 hours of sun a day. If you have to choose between a site with morning sun vs. one with afternoon sun, choose morning. That way, the morning sun will dry any dew on the leaves, minimizing disease problems.
Space Roses Properly
A general rule of thumb is to space roses at least 24 inches apart, but take note of the type of rose you are planting. Large shrub roses and rugosas should be spaced further apart, while miniatures can be planted a little closer. Err on the side of too much space, since good air circulation is critical for healthy plants.
Choose Disease-Resistant Varieties
A rose variety's resistance to common rose diseases, including black spot and powdery mildew, should be at the top of your list of positive attributes. Sure, a certain variety may have spectacular flowers, but if it succumbs to disease you won't be able to enjoy them. Unless you are committed to a diligent pest management program, go with the disease-resistant variety. There are lots to choose from!
Begin Unwrapping Roses
If you wrapped or otherwise protected your roses for the winter, begin unwrapping them in late March. Do this gradually, so the plant awakens slowly as the weather warms. Begin by removing whatever you used to protect the top of the rose, and gradually remove the protective mulch.
Apply Fresh Mulch
Many disease organisms overwinter on fallen foliage or in the mulch underneath shrubs. Rake the area beneath your shrubs and apply fresh mulch. Pick off any leaves that remain on the shrub from last year, as well as any rose hips on roses.