I do not grow Harmony's Cotton Candy - but I have Tea's Blueberry Butterfly and RS-Zhar Ptica. The blossoms are this combination of blue, white and yellow. In my experience the amount of yellow is very variable and depends on a season. Summer is not the yellow time. Spring and fall are.

Since yellow is not a pigment that comes naturally - there is no consistently yellow varieties so far. You can get the yellow streaks in one bloom cycle - and cream color next time.

Check the spelling - the correct name comes from Harmony's Greenhouses in FL. You can google the photos easier. I think it is an interesting plant to have.

Yellow is very inconsistent. I wrote a research article about it for my club and did a presentation because one of the seasoned growers was trying to grow yellows. Jeff Smith in the AVSA publication in several articles explained the very complicated genetics that create the look of yellow. It is not an actual pigment. You could ask the grower their opinion, if it blooms true. Also, if you can buy directly from a professional grower, especially the hybridizer, you will get better stock and a guarantee. As a new grower, do try growing a few solid colors such as blue or pink. That will give you something predictable so that if the exotics underperform, you will have something that is rewarding.