I used Penny Black's scarlet majesty cling stamp with SU!'s Magenta Madness ink for the Poinsettia and love how it came out in just the single color! My sentiment comes from Penny Black's rejoice with joy stamp set and I used Concord & 9th's MIDNIGHT (navy blue) ink.
I used a few magenta colored sequins for my embellishments on the Poinsettia and that was all the card needed for both challenges and it still came out CAS too!
You can check out all the details for the Color Hues Challenge HERE and the details for The Flower Challenge right HERE.