A: Happily, no.
Hollies, Magnolias, and other evergreen varieties, have long-lasting leaves that do not drop for the winter. Long-lasting does not mean eternal! Periodically, the plants will shed less-useful leaves that are now partially shaded by new growth, or leaves which have been stressed or damaged by environmental conditions.
This is not a sign of anything at all going wrong. Fertilize your hollies and magnolias now with our Covington’s Tree and Shrub Fertilizer if you haven’t already fed them this year. The yellow leaves will drop off, and the plant will be perfectly fine.
As a special note, we have seen a lot of magnolias showing damaged leaves from the two hail events that moved through the area this spring. The worst damaged leaves will fall, the rest will stay as they are, and new growth will improve the tree’s appearance. Again, other than fertilizing, no special treatment is required.