Some Cacti are Tender to Winter Freeze Here

Q. I have a 5-year old Prickly Pear cactus. I brought it here from Florida in 2015 and started it by planting the pads. I’m seeing some yellowing starting to develop where the spines are located. I am familiar with cochineal scale and I don’t think it’s an insect problem. What’s causing this and how do I correct it?

Damage to the cactus. Perhaps from cold temps.

A. Most likely this is cold damage from low winter temperatures. Most of Florida is warmer than our Las Vegas climate. Your prickly pear cactus from Florida has never seen temperatures as cold as we get in Las Vegas. Prickly Pear, a.k.a. Opuntia cactus range in their tolerance to freezing temperatures from damage seen at 32° F down to 10° F. It depends where that cactus was originally growing.

This is the type of freeze damage that I am used to seeing on prickly pear cactus.

These were nopal cactus from Sonora but grown in Las Vegas where winter temps were just a bit too cold for them.

            Opuntia cactus are native to Central and North America with some types growing in the warm Sonoran Desert and others in our colder Mojave Desert. Pads used for propagating this cactus coming from the Sonoran Desert will not tolerate the freezing temperatures of the Mojave Desert. But Opuntia grown from pads taken from the Mojave Desert will.

Next spring growth may come at the center of the pad after winter freeze damage.

            In the future don’t apply any fertilizer to tender Opuntia after July 1. Not applying late summer or fall fertilizers improves their ability to withstand freezing temperatures. For a similar reason, start withholding water from Opuntia to slow their growth in the early fall months. Not encouraging new growth by withholding fertilizer and water helps to hardened them off for the cold winter months.