Check out the Deciduous Azalea 'My Mary' which are offered by the supplies in your part of the country. This is a Beasley hybridized cultivar award winner.

Last year I receive one which had been shipped in very good condition. It shipped from a Carolina nursery and arrived with two 3' tall main leader branches that had a single bud on each leader top.

In February this spring I planted that azalea at my Daughter's house in Fort Worth, TX. She raved at how pretty she thought the flowers were. This azalea will most likely bloom a week or two later in your area compared to her's which just finished blooming this past week.

There are some suppliers of My Mary 'Rhodendron x My Mary'deciduous azaleas who claim it will grow up to 5 feet in 10 years. Other supplies simply says it will grow up to 8 feet.

In May I plan to take a fasigatia Plum Yew to my daughter and plant it as a nice evergreen backdrop for her decidous azalea.

You will simply need to check out the 'My Mary' distributors in your are to see if you think the forms of this cultivar they sell will enhance your purple blooming azaleas.

A white blooming deciduous azalea in the spot you described might also look very nice.