Geraniums are known for their beautiful blooms and low maintenance care. Single and double blooms occur in white, red, pink and salmon colors.
The ideal outside daytime temperature for geraniums is between 70 and 80 degrees, and the ideal nighttime temperature is in the 60s. Geraniums can live through the winter in some areas, though cold damage may cause devastating effects to the plants.
Signs of cold damage on geraniums include red leaves and wilted blooms. Stems may break away from the plant. Cold temperatures also cause stunted growth in geraniums.
Geraniums become more susceptible to cold damage when not properly planted. Geraniums with weak root systems will suffer cold damage faster than those with strong root systems.
Plant geraniums in well-drained soil, regardless if they are planted in the ground or in containers. Add a layer of mulch around the base of the geranium to protect roots during the winter.
Do not prune geraniums immediately after a cold frost. Dead or decaying branches help protect new growth on the plant. Wait until winter has passed before pruning away branches. Use garden shears to prune away weak branches on geraniums.
Geraniums planted in containers are more susceptible to cold damage than those planted in the ground. Covering these containers with sheets or plastic tarps helps protect them from frost. Confirm all sides of the container are adequately covered, because one side of the geranium may still suffer cold damage if not protected.
Prevention is the best way to protect geraniums from cold damage. Watch the weather forecast carefully during winter months. Note that most cold damage occurs due to a low internal plant temperature and not the actual frost itself. Be prepared to cover or bring geraniums inside if needed during cold nights.
Geraniums exposed to colder temperatures on a regular basis have a better chance of survival than those surprised by an unexpected frost.