Saguaro Spines Turning Black: Normal Aging, Not Disease

Black Spine Tips on Three Saguaros—Others Unaffected

Three saguaros have spines turning black (mid-stem on two, top on one). Plants otherwise look healthy. Owner asks if this is normal or a problem.

Spines Are Dead Tissue—Color Change Is Natural

Greg compares spines to fingernails: the visible part is dead keratin. Spine color often changes with age (new spines at the top are darker). If there's no foreign substance (soot, fungus, insect residue), it's normal.

When to Worry

• Black, soft, mushy stem tissue = rot.
• Powdery or fuzzy coating = fungal/pest issue.
• Send a photo to greg8365@hotmail.com if unsure.

Otherwise, enjoy the color variation—it's part of the plant's maturation.