That’s just an absurd premise one might say. A 150 year old saguaro getting a sunburn? A rugged barrel cactus getting a sun burn? Your latest home depot cactus you just planted getting a sun burn? Your dish garden sitting in your window getting a sunburn? Yes! All of these circumstances are possible.
Let’s think about the sentinel of the Sonoran desert. The mighty saguaro. Starting from seed, growing tall and mighty against the relentless Southern Arizona sun. From an installation perspective, the saguaros we harvest have to be directionally marked prior to being dug up for resale. We must keep the North-South orientation correct because if the orientation is not true upon planting we will get a sun burned saguaro. The reason is that the South and West sides of the plant receive much more direct sun than the East and North sides of the plant. The Southern side gets the most sun while the Northern side of the plant receives the least amount of sun. The Southern and Western sides of the saguaro have become hardened off to our relentless Southern Arizona sun while the East and North sides are much “softer”. The same rules apply for barrel cacti, columnar cacti and even if you rotate your dish garden sitting in your window.
The cacti and succulents you can buy at a typical big box store can burn for another reason. They were grown “soft”. This simply means that the plants were grown under shade cloth and are not accustomed to the full sun. There are a few ways to deal with a “soft” cactus. The first is to buy your cacti from us because our plants are hard grown in the Southern Arizona sun! The second is to plant a “soft” succulent or cactus in the Fall and let the plant gradually become accustomed to the increased strength and duration of the sunlight. If you must plant a softly grown cactus in the summer be prepared to put 30% shade cloth over it until the Fall to prevent burning.
What does a cactus sunburn look like? The nice green flesh of the cactus will turn lite green. Then yellow and then white in its’ most severe form. Sunburn is not a terminal condition but you will be left with significant scarring in the affected area for many years.