It is an Encore Azalea. They have a website. Here is what their website says:

A robust upright variety with deep green foliage and large, rich purple blooms, Autumn Royalty was voted Azalea of the Year by the American Rhododendron Society.
Growing & Maintenance Tips:

This plant prefers slightly acidic, well-drained soil.

Bloom Color - Dark Purple

Arbor Day Hardiness Zones: # 7, 8, 9, 10

Height: 4.5 feet

Spread: 4 feet

Bloom Span: 3.5 inches across

Bloom Form: Single

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The Encore Azaleas bloom as other azaleas in the spring. Then after the new growth comes out in the summer, they bloom again on that until the fall. They are primarily grown in the South. I haven't seen any.

Here is a link that might be useful: Encore Azaleas

this is the first encore azalea that i planted and my largest. it took several years to begin to perform as they claim with regards to blooming after initial spring flowering. it was beautiful this spring and last fall so i am hoping that it will continue to produce a nice fall flush of flowers. the preceeding years were disappointing in that respect with almost no fall bloom. i do not get many (if any) flowers during our hot, dry summers here.
this one looks nice paired with 'autumn twist' which has white flowers with irregular purple streaks.

Thanks for the input Jeff. I have never seen Encore Azaleas and hence have never grown any. It is great to get a first hand report on their performance. Good luck.

Thanks for the info Rhodyman and Jeff. Jeff, do you feed it regularly? Maybe that could mean something that it didn't bloom for a few seasons.

no, i don't fertilize my azaleas. most of them perform very well in the southern u.s. because the climate here is similar to their native ranges(possibly the soils are too?). camellias are like evergreen azaleas in that respect and we have adopted that as our state flower in alabama.
i really can't say why about the reluctance to flower heavily in the fall on a regular basis. i don't think it is a nutrient issue because the foliage looks good and they do flower well in the spring. could possibly be site-related as i plant them in semi-shade and some information i have read says they prefer more sun than most azaleas.
either way, any flowers that i get to see after spring are just a bonus.