You don't have a little microclimate going on where they are too cold, do you? Buds forming but no flowers resulting? White varieties of Southern Indica will have buds killed at 22F.

Other reasons for failure to bloom would be drought in summer, too much shade, and overfertilizing with a high nitrogen fertilizer will produce vegetative growth while inhibiting flower bud formation.

Well, the temperature does drop below 22 degrees several times each winter in my area, so maybe it is too cold for the Delaware Valley azaleas. I haven't seen any buds on them, but they produce new leaves each spring and summer. It's a mystery to me.

Having been born and raised in the "Delaware Valley" (LOL), if your DVW decided to swell its buds a wee bit too soon and then got a late frost, then I expect they would be toast. My mother has 2 that are just starting to bloom right now (her kurumes are fully out and have been for about a week). Both my sisters also have 1-year plantings of DVW that are starting to bloom now as babies. These plants have been through a few single digits this past winter so they are pretty hardy.

The buds on yours should have formed back last fall, so if you didn't see any, there might be some environmental conditions inhibiting bud formation. How's the soil pH?

This was my mother's a couple years ago:

{{gwi:387165}}

Meant to take a pic of it today since I stopped by, but I wanted to wait until they were fully open.

I have not had my soil pH tested, but that could be the problem. I also recall the year I planted these two azaleas (2000), we were in the middle of a 4-year drought, so they probably didn't get off to the best start, but that doesn't seem to have affected most of my other azaleas much.

Are they getting enough sun?

One of them has full sun almost all day, and the other one has full sun for about half a day, in mid-to-late afternoon.

It could be that with the full sun, they need some extra deep watering during the summer when they are setting buds for the next season. The above-pictured ones are west-facing and get overhead 1/2 day afternoon sun with some dappled sun late in afternoon due to the large old sycamore trees across the street. When it is dry and hot in the summer, my mother will stick her hose down into the soil at the middle of each one, turn the flow down low, and let it run for about 20 - 30 minutes. Perhaps in your case, if you can give them some extra water this summer, it might make alot of difference regarding whether they will set buds this year. Doesn't hurt to try. :-)

Try giving them a shot of super phosphate this summer.

Thanks for all of the advice...I will try some of your suggestions and we'll see what happens next spring! Hopefully this summer won't be too hot and dry for them!

Good luck with the efforts. They are well worth it!

I did manage to stop by my Mom's today and her DWVs are open:

{{gwi:387167}}

One of my sisters bought her 2 new babies for Mother's Day.

{{gwi:387169}}

My first and I’m in love!! But the size and evergreen part works very well where I need it too.