Will they bloom at all this year?

Unless you way overdid it with the Miracle-Gro, it doesn't seem very likely this could have totally eliminated any bloom. Are there still flower buds visible? Rhododendron maximum and many of its hybrids as well as some other varieties do not bloom until much later than mid May - some as late as early July.

If there are no buds visible and none were apparent last fall, avoid using any fertilizer this year and things will return to normal for spring 2011. One of the problems with Miracle-Gro is that it is quick acting with very short lived effects.

If there were buds last fall, but none now, I'd suspect browsing deer.

I have no idea about last fall as we just bought the house in February. Currently there are no buds whatsoever. There is, however a ton of new leaves.

I assume there were no buds in February(?)and this was the time you used the Miracle-Gro. If deer are a problem in your area, that still might be the explanation. They can be very neat about nipping off just the buds. If deer are not an issue, then some other factor prevented normal bud formation. The previous owners may have over-fertilized, or perhaps pruned off last year's buds to make things look neater. Excessive shade can also reduce bud set but generally does not eliminate it entirely.

The crop of new leaves, if it seems really excessive, is a result of an over supply of nitrogen from the fertilizer. Things will eventually return to normal with bud formation in the late summer/early fall and bloom in the spring. You may, however, have to wait for spring of 2012 if the fertilizer dose was really excessive.