Daisy,
I grow both Navy Blues and Blueberry Bliss. Navy Blues blooms much earlier in the season than Blueberry Bliss, so you could grow both of them for the deep blue impact. Blueberry Bliss increased very well and was a beautiful clump its third year.
My Navy Blues grows a bit more slowly, but two rhizomes of NB grew into this clump in two years.
You can see that BB has more buds than NB, but as I say, they bloom at different times.
