Should Heritage Roses Be Pruned in California?

Climate Zones

• Most roses have evolved to require a period of cold weather dormancy before the plants bloom in the spring. Parts of California, especially Southern California, that lie in U.S. Department of Agriculture plant hardiness zones 9 and higher, do not have or have consistently the winter temperatures required to induce dormancy naturally. In these areas, pruning creates artificial dormancy. Other reasons for pruning are consistent wherever roses are grown -- to rid the plants of dead or weak canes, promote air circulation, stimulate rebloom in varieties with that trait and create an attractive shrub.

Winter Pruning

• Prune heritage or old garden roses in January or early February. Remove any dead canes and cut all other back by one-third or one-half for very large shrubs. Trim off any foliage that remains on the plant and discard. In general, trim with sharp clippers or secateurs and clip canes just above outward facing leaf buds to promote good growth habit. Remove crossed canes and prune so that the shrubs have a vase-shaped habit. Seal the ends of newly clipped canes with a drop of white, all-purpose glue.

Once-Bloomers

• Some of the greatest of the heritage or heirloom roses, like the wonderful old alba "Cuisse de Nymphe Emue" also sometimes known as "Maiden's Blush" (Rosa "Cuisse de Numphe Emue"), hardy in USDA zones 3b through 9b, are once-bloomers. Other types of roses in this category include other albas (forms and hybrids), gallicas (Rosa gallica and hybrids), moss (Rosa centifolia muscosa and hybrids) and centifolia (Rosa centifolia and hybrids). In California, as elsewhere, these once-bloomers should be pruned in late spring or early summer, after they have bloomed.

Repeat Bloomers

• Bourbon roses, like the cerise-colored "Zephirine Drouhin" (Rosa "Zephirine Drouhin"), hardy in USDA zones 5 through 9, are repeat bloomers. Other old roses in this category include hybrid perpetuals (complex hybrids of China, Portland, Bourbon and other rose types), many damasks (Rosa damascena and hybrids) and Portlands (complex hybrids related to damasks). To stimulate rebloom in California and elsewhere, these roses should be pruned lightly after each bloom cycle. Many old garden roses are sold on their own roots, producing bottom growth that is true to type, but for grafted varieties, watch for root suckers and remove promptly.