Climbing plants can greatly help moderate temperatures. When grown on the walls of a home or building, they keep it cooler in summer by reflecting the sun’s rays and also by lowering the temperature through transpiration. Most lose their leaves in the winter, thus letting the sun warm the house… and their intertwining stems moderate the wind, reducing heat loss.
And the effect is felt in the garden too. The green curtain created by vines covering a pergola can reduce the temperature by up to 7˚F (4˚C), a significant difference on a hot summer day.
The temperature-reducing effect of vines is most obviously felt in the city, where, under the pervasive influence of asphalt and concrete, buildings become real ovens in the summer. One of these days city planners will wake up to this fact and start making growing green plants on city walls an obligation.
Of course, you’ll probably wonder if growing vines on a wall doesn’t harm it. The answer is no. Here is a blog on the subject.