We're trying stem dye this year for St. Paddy's Day.  We have, in the past, bought in our green carnations already stem dyed but this year, at the suggestion of our flower salesperson Linda, we've been dyeing our own.  The first "experiment" involved 1/2 hour vs. 1 full hour in the same concentration of dye, 1t./qt.  The 1/2 hour treatment was definitely enough.  We'll post a pic soon.