How Cold Hardy Is a Gemini Rose Bush?

Cold-Weather Tolerance

• The U.S. Department of Agriculture has established planting zones throughout the country to aid growers in determining whether a plant can survive exposure to low temperatures. Perennials able to withstand very cold, subfreezing temperatures are known as being cold hardy. The “Gemini” rose is such a rose, able to withstand minimum temperatures in USDA plant hardiness zones 3 to 11. For example, in USDA zone 3, winter temperatures can plummet as low as minus 40 degrees Fahrenheit. With such a cold-weather tolerance, the “Gemini” hybrid tea rose can be planted in areas of northern states such as Maine, Minnesota, Montana and even Alaska.

Healthy Plants Are Hardier Plants

• Even with its inherent cold hardiness, the “Gemini” rose will have better tolerance of extreme cold if the bush is kept healthy and well cared for year-round. Rose bushes weakened by disease, pest infestation or nutrient deficiency are less likely to withstand harsh winter conditions. Adding a 2- to 4-inch layer of mulch around the rose plant base will help retain moisture in the soil and keep weeds at bay. A carefully planned feeding schedule, with fertilizer added in early spring, during the first bloom, and in mid- to late July, is also essential. Feedings after July 31 are discouraged, because new growth at this time will be vulnerable to cold-weather temperatures. Also, reduce risk of fungal infection by applying fungicides as a preventative, especially during rainy periods.

Pruning Before the Cold

• Although a “Gemini” rose should not be pruned severely in the fall, some cutting back is recommended before winter sets in. This variety of hybrid tea rose typically reaches heights between 5 and 6 feet, which makes higher branches susceptible to wind and cold damage. First, remove any diseased or damaged canes. Then, cut back the remaining tall healthy rose canes to about 24 inches. The general rule of thumb for hybrid tea roses is not to prune canes back to less than 18 inches in fall. However, if a “Gemini” bush has suffered cold damage below this height in the past, a more aggressive pre-winter pruning may be warranted.

Winterization

• Even cold-hardy roses such as “Gemini” can be susceptible to injury at very low temperatures and require additional protection over winter to ensure healthy spring growth. The base of the “Gemini” bush should be protection with an 8- to 12-inch mound of loose soil, compost or aged sawdust that drains well. For additional protection, top the mound with straw or evergreen boughs. In areas with more severe winters, the rose bush can be further winterized by covering with a protective cone or burlap wrapping.