Have you checked for a spider mite infestation? There will be webbing at the crux of the leaves and if you tap the leaves over a piece of white paper, you will see tiny black or red 'specks' - spider mites.

I had one in a pot that developed the exact same symptoms during the summer. I decided it didn't like being in a pot. I transplanted it into my greenhouse (actually more of an arboretum) where the temp in winter is around 50. It has rewarded me greatly with tons of flowers all summer. Right now it's putting on new growth. Do you have a place in the ground for it?
Carol

A friend has them planted all along his house in a low planter box, by the mailbox, etc. I was shocked when I went over to his house one day and they were wacked down to nubby nothings (no leaves or flowers left for photosynthesis!), and within 2-3 weeks they had started to leaf out and flower again! He told me the only thing he does to them is cut them back 2 x a year, otherwise no supplemental water (doesn't have a sprinkler) or fertilizer. I tried to root some cuttings but they didn't work out but I'm going to try again. They are very profilic bloomers given the right conditions (??? total neglect & abuse???) By the way my friend is 91 years old and has had these same allamanda's for over 20 years :) Hope yours does better soon!

I have a allamanda that has not bloomed yet this year. It looks healthy, but by this time last year it was flowering like crazy. We live in IL. Anyone have any ideas? Thanks