Sounds like fertilizer burn, or the effect of a fertilizer that was applied too strongly. Typically this wears off pretty rapidly and is helped by frequent watering, although the foliage may not come back immediately.

Make sure you follow the directions on the fertilizer package exactly - in fact, I suggest applying any fertilizer at a slightly lower rate than recommended and a bit more frequently (if necessary). This way you run much less of a risk of over-applying. And don't fertilize a stressed or sick plant, immediately after planting or in the height of the growing season. Fertilize only as new growth commences in spring or with woody plants, lightly with a low nitrogen fertilizer in fall.