I'm sure the recipe would work fine with yellow mustard seeds as well, just wont be as strong. (canned-time.com)
I'd say you'd be safe to go with a floral print of your flavor or a fall color of mustard yellow, orange, navy blue or forest green. (thefashionfolks.com)
This recipe would also be terrific with mustard greens in place of the spinach, although you'd have to cook the greens for a minute or two longer. (whatwouldcathyeat.com)