My rhubarb is called Canada Red, but it stays green and never turns bright red as I expected. Is there something it needs to achieve its red coloring?
—John Pomarzynski, Baltimore, Maryland
If the stems (actually petioles) were never red, it is possible you received a green-stemmed variety by mistake. Or, just like people, your plant is unique and just won't turn as red as most others.
If the once-red stems are now green, we need to look at the environment. Excess shade can cause red-stemmed plants to fade to green.
Generally, you will have the best color and flavor with cooler temperatures. If heat or shade is the problem, consider moving the plants to an east-facing location where they will receive plenty of cool morning sunlight.