Decidious azaleas?

I'm just curious - are certain azaleas decidious to the point of almost complete defoliation in Autumn. I've had this one for 3 or 4 years now but it's never lost almost its entire leaves in the space of a week or two before. :(. I've another newer one in an ordinary pot that's done the same too though not quite as dramatically perhaps. The bonsai one is in part soil and part grit with a top layer of kanuma grit which is supposed to be for azaleas while the other is just in a pot of ericaceous soil. Both were fed well through the summer with an ericaceous feed (Green Dream) and watering was reduced as soon as the weather got cooler & wetter.

Any encouragement appreciated.

 

If it is a deciduous azalea then it will lose all its leaves in winter.
I think all azaleas are now classified as rhododendrons, but I seem to think azalea was always deciduous.
Not an expert by any means.

 

Azaleas can be deciduous or evergreen. I have both here.
An important factor in growing azaleas in pots is not to mulch too heavily. A soil based ericaceous compost too is important.