I am doing an experiment placing cut white mums in red water and watching them change colors, and then watering white mum plants in pots and not expecting any color changes. However, after 2 weeks of red watering, two of my three mum plants (all white) show some purple on the tips of several of the flowers. Does this ever happen with white mums, or is my red water doing something it is not supposed to? The process of becoming colored for the cut flowers was to see red lines in petals, followed by a gradual pinkening of the whole flower. The purple on the potted plants is not at all the same color, and it is little blotches of color rather then lines. I am confused, but was hoping someone more familiar with flowers would know more. Thanks!
One possibility--are you watering overhead with a watering can? Could be you're splashing some of the food coloring water on the white mum flowers. You wouldn't notice it at first because the dye in the water droplets is pretty dilute, but as the water dries the dye gets left behind. That could definitely explain why you're seeing weird looking spots and blotches. And some dyes will react in the air to form different colors than they were originally, so that could be why the color looks a little different.
I wouldn't have thought the roots would take up much of the dye, but since I've never tried this myself I guess it's possible that the plant is taking up some of it. Some of the dye molecules may be able to be transported up through the roots and into the plant and others may get left behind (or some of them are reacting with things in the soil and changing color), that could be why the color looks different.
Pink and/or purple tips on white mum flowers is a pretty common occurence as the flower ages, so I doubt the red in the water has anything to do with it.
The cut flower industry dyes flowers three different ways: Stem dying, in which the flower stems are placed in water with dye in it, and the capillary action absorbs the dye into all parts of the tissue, but shows up more in the flower petals. Head dip dying is used when they just dip the head of the flower into dye...some flowers absorb the color faster and more intently than others. The third method is actual spray paint for flowers.
You can test method #1 by taking a stalk of celery and placing it in water with food coloring in it. The celery will eventually take on some/ or much of the color depending on what the color is.
The "pigment" in water soluble dye is lost to soil particles by absorption almost immediately, and any vestiges of it that remain are in such minimal amounts that even when taken up by roots will barely be noticeable, if at all.
The flower industry comes up with some pretty garish looking flowers when they stem dye some things.
Thank you for the responses. I am pretty sure that I have not spilled any dye when watering. I was not aware that the plants ever got purple or pink on them as they aged. That seems like it could be what is happening, as the purple is on the tips of some of the more wilted and aged looking flowers. It is not on the healthier flowers that still are well-formed with no drooping petals. All three of my pots have some purple now, but the most purple is on the plant that is the most past it's peak. I appreciate both your responses.
I don't think that the colouring will make it to the flowers by watering the plant with foodcolouring, otherwise the blue dye from miracle grow would show in flowers too. I have put carnations in food colouring and it goes to the petals that way, but only as a cut flower, with no roots as Jasper suggested.
i'm kinda late to this thread, but all the white and yellow mums here have turned reddish or purplish at the tips of the petals both of the years they've been here. The 1st year i thought it was from the dyed mulch the owners put down, but it happened this year too.