<a href=showthread.php?s=&postid=14635575#post14635575 target=_blank>Originally posted</a> by massman
Whilst I also am against this practice, I have as a controlled experiment years ago dyed four specimens of h. malus by soaking them in food colouring. (fit for human consumption)
All absorbed the colour but eventually lost it returning to their normal cream/brown colour. (over about a 4 week period)
No adverse effects were noticed. In fact, I still have one of these anemones to this day (4 years later).
However, I must say that the colours were never as solid as those pictured.