Why Does a Rose Bush Go Dormant?

Reduce Water Loss

• The frozen months of winter means considerably less water is available for rose plants. To deal with this condition, roses break down the chlorophyll in the leaves and drop the leaves from the branches. Dropping the leaves produces less surface area from which water can be evaporated.

Natural Antifreeze

• Roses are multi-cellular organisms. Their cells cannot survive if frozen, so the plants create a natural antifreeze that prevents the stems from freezing. Colloid is a thickening agent found in cell sap. During dormancy, the colloids thicken. The thicker sap is more resistant to freezing, and thus it can sustain the rose through the winter snow.

Bud Protection

• During the winter dormancy, roses are forming buds for the next year. However, those buds must be fed and protected. This process cannot happen if the plant is expending resources through the leaves. So, roses drop the leaves and give the nutrients to the newly developed buds.

Root Growth

• Just because the top of the plant looks dead does not mean that the bottom of the plant is dormant as well. As long as the soil's temperature remains above 40 degrees Fahrenheit, a rose plant's roots will grow and extend further into the soil. The larger root system provides greater nutrient absorption through the next season.