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.
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.
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.
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.