I've looked at literally millions of saguaros in my travels, and these are the only ones I've ever seen with this yellow coloring. Cactuses with non-uniform coloration are known as variegated cactuses. Variegation is due to a rare mutation wherein the plant's meristematic tissue loses the ability to produce cholorplasts, causing a lack of chlorophyll in the epidermis..
This saguaro has two arms that are a bright yellow color instead of green. Variegation usually occurs in irregular blotches; for a complete arm to be discolored like this is very rare.
Thanks to Phil K. for directing me to this cactus.
Last Visited: January 2012. Now gone due to road construction.
This armless saguaro is the normal green color at its base, but gradually transitions to bright yellow.
Last Visited: May 2013.
This saguaro has a small patch of yellow on one side of one arm.
Last Visited: September 2013.
One side of one arm of this saguaro is yellow.
Last Visited: November 2013.
This short saguaro has an irregular patch of yellow running up one side.
Last Visited: December 2013.
This saguaro has just a small patch of yellow high on one side.
Last Visited: February 2014.
One entire side of this short saguaro is bright yellow.
Last Visited: November 2014.
This entire saguaro is colored yellow / yellow-green.
Last Visited: April 2015.
Telephoto shot of twin saguaros that are such a pale yellow that they appear to be "albino" saguaros.
Last Visited: November 2015.
A single "albino" saguaro not far from the twins shown above.
Last Visited: November 2015.
The top half of this saguaro arm is a bright yellow.
Last Visited: December 2015.
This entire saguaro is colored yellow / yellow-green.
Last Visited: January 2016.
A small patch of yellow on one arm is the only clue that this saguaro is variegated.
Last Visited: February 2016.
Telephoto shot of yellow / yellow-green saguaro in the distance.
Last Visited: February 2016.
Telephoto shot of golden saguaro in the distance.
Last Visited: February 2016.
Thanks to Don E. for giving me directions to this saguaro.
Full golden saguaro.
Last Visited: March 2016.
Thanks to Don E. for giving me directions to this saguaro.
One side of this armless saguaro is pale yellow at its base, but gradually transitions to bright yellow at it tip.
Last Visited: March 2016.
One side of this armless saguaro is yellow at its base, the other side the normal green.
Last Visited: April 2016.
One arm of this saguaro is mostly yellow, with some green patches.
Last Visited: April 2017.
One arm of this saguaro is mostly yellow, with some green patches.
Last Visited: April 2017.
Telephoto shot - this short armless saguaro is completely yellow.
Last Visited: April 2017.
Telephoto shot - this short armless saguaro is mostly yellow.
Last Visited: September 2017.
The top half of this armless saguaro is solid yellow.
Last Visited: December 2017.
This short saguaro is a solid golden color.
Last Visited: March 2018.
Extend-O-Cam view - this saguaro has one short golden arm.
Last Visited: February 2020.
Extend-O-Cam view - this saguaro has two small golden arms.
Last Visited: February 2020.
Irregular yellow patches run up the sides of this saguaro.
Last Visited: April 2020.
Telephoto shot - this saguaro is almost completely yellow.
Last Visited: April 2020.
Telephoto shot - this saguaro has one tiny golden arm.
Last Visited: November 2020.
The upper trunk and one arm of this saguaro are golden.
Last Visited: January 2021.
This saguaro has one mostly-golden arm.
Last Visited: January 2021.
The upper part of this short saguaro has golden patches.
Last Visited: November 2021.
This saguaro has one golden arm.
Last Visited: January 2022.
The upper part of this saguaro is golden.
Last Visited: Febuary 2022.
This saguaro has a golden patch running around its middle.
Last Visited: December 2022.
This saguaro has a golden blotches on the upper part of one arm.
Last Visited: December 2022.
This saguaro has a golden patch on one side of its trunk.
Last Visited: January 2023.
This young saguaro has a golden patch running up one side of its trunk.
Last Visited: January 2024.
The trunk of this saguaro is almost completely golden.
Last Visited: February 2024.
One arm of this saguaro is golden. Discovered by Harry Ford.
Last Visited: April 2024.
Locations undisclosed to prevent vandalism.
Standard disclaimer: Sites are described for entertainment purposes only, as they were at the time of my last visit. I can not vouch for the current condition of the site or its accessibility.