Q.Why is bottom part of gladiolus red and can I pile rock up around it ?
I have gladiolus and want to know if I can pile rock up around stem and why part of stem is red rather then green it’s 43 inches tall.

Certified GKH Gardening Expert
It's hard to say whether the different color at the base of the stem is a problem or just a natural occurrence, since much of the energy is concentrated there. Check out this article: https://ipm.illinois.edu/diseases/rpds/651.pdf
The rocks shouldn't present a problem but if they are to hold up the gladioli, do it very loosely so as not to damage the stems. Here's an article with more info about how to grow them and one on staking glads:
https://www.gardeningknowhow.com/ornamental/bulbs/gladiola/care-of-gladiolas-how-to-grow-gladiolas-in-your-garden.htm
https://www.gardeningknowhow.com/ornamental/bulbs/gladiola/staking-gladiolus-plants.htm