Yellow irises were always a popular hybridizing goal in the early years and many were introduced. Most were small flowered and short and breeders worked for decades to deepen the color, enlarge the flowers and add height to the bloomstalk. It was slow going. One of the best early ones was 'Coronation'. A creation of Mrs. John Beverly (Connie) Moore of Benton, IL, it was introduced in 1927 to rave reviews.
Tho not a large flower it was larger than most yellows of its day and it had two other traits going for it as well - height and color! In my garden it will bloom early on stalks around 40" in height. A reliable bloomer, the flowers are profuse and in cool temps are a very deep golden yellow, while buds opening in warm temps tend to be lighter. The beards are a matching shade of yellow. Because of the profusion of blooms it tends to put on a long display. It is a wonderful variety for mass plantings in long drifts.
Another feature, which some may think detracts, is the tendency to have a light dusting of purple freckles around the upper fall area. They seem more prominent during cool temps and not so noticeable when buds open on warm days. I think they are cute and always watch for them.
'Coronation' is a very hardy iris that thrives just fine in neglect and so is often seen growing around the US. It is one of the most common irises sent to me for ID. This would be an ideal variety for those with very tough climates. In addition to the wonderful traits already mentioned it also has great purple based foliage (pbf) which adds interest even when the flowers aren't around. 'Coronation' has it all, and is truly an iris classic.