This was a tough color challenge, especially in Winter! The only thing that comes to my mind with these colors (Summer Sun, Certainly Celery and Old Olive) are Sunflowers or Dandelions!! So I went with it.
I cheated with the A Muse Madeira Green notecard but it's pretty close to Certainly Celery and you could easily sub CC for this notecard! This might also qualify for SC63 cuz it folds up and tucks under the slit punch. But SC63 calls for a 5x5 card.