I am guessing they are either late azaleas called Satsuki Evergreen Azaleas or early azaleas called Tsutsuji Evergreen Azaleas.

The Tsutsuji azaleas bloom one lunar cycle after the spring equinox. In Japanese, I am told that Satsuki means fifth month of the Japanese lunar calendar (June). So plants bloom late (May, June and July), when most other azaleas are no longer blooming.

Flower colors vary from white to pink, yellowish pink, red, reddish orange and purple. Color patterns include solids, and stripes, flakes, lines, sectors and margins of color on a lighter background. The complete range of color patterns can appear on the same plant, differently each year. These color patterns are highly prized by the Japanese, and were carefully described and classified starting as early as 1692 in the book A Brocade Pillow. A Brocade Pillow has been translated into English, but I assume the original version is still available.

Here is a link that might be useful: Japanese Azaleas

Thanks Rhodyman,

Yes indeed, the pink ones I have are tsutsuji (very small leaves) but most are Satsuki. I'll look into getting a copy of the Brocade Pillow link. Rgds, Ptaro