They generally don't need amended soil. They do like moist soil bordering on wet. Mine grow in partial shade,but not mostly shade in clay soil. You may be over doing it with the fertilizer or causing the soil to be too acidic with the pine straw. The other possibility is that they are in shock. I wouldn't worry. They grow back fairly fast. Just keep them well watered and they will be fine.

I've found that elephant ears always do this when you transplant them. You can just cut the stems off a couple inches above the ground, keep them watered and they should come back some this season, but may not see good results til next year. They do best if you transplant them in the fall, I find.

I agree with bayou10. Right now, their leaves are too big for their root systems. Cut them back, and while they won't reach full glory this year, they'll be their regular huge selves next year.

Even when fresh, pine needles are only slightly acidic and therefore can have limited effect on changing the pH of the soil.

...12 years later!