Grab a branch & turn it over to see the underside of the needles. Adelgids will show as small, numerous, whitish fuzzy dots clinging underneath. And yes, they will cause yellowing. I don't think the adelgid is in Georgia, tho. Hemlock is not heat/drought tolerant, so that may be the reason.

DEFINITION: The hemlock wooly adelgid (HWA), Adelges tsugae (Annand), is an aphid-like insect that originated in Japan and that infests hemlock species. It was first introduced into this country on the west coast in British Columbia in the 20s, and then was found in Virginia in the 50s. These were presumably separate, accidental infestations. OCCURRENCE: Since the introduction in Virginia, HWA has rapidly moved up the east coast to New England and is devastating both the eastern hemlock (Tsuga canadensis) and the Carolina hemlock (T. caroliniana). Major infestations are found in states from North Carolina to southern New England. There are quarantines in effect in Maine, New Hampshire and Vermont which regulate the movement of hemlock seedlings, nursery stock, and various lumber and bark products from infected areas. DAMAGE: The HWA attaches to the stems at the base of the needles and both kills the needles and prevents new growth. The tree often dies within 4 years, although some trees will survive longer while exhibiting diminished growth. If untreated, death is almost inevitable. LIFE CYCLE: There are two generations of HWA per year. During March and April the adults lay eggs in a cottony mass, which hatch into larvae in April and May and which soon attach to the young hemlock twigs. They then settle down and feed until they mature into adults in mid-June. This new adult generation has one odd feature some of the adults are winged and can only reproduce on certain Japanese spruce. The winged form sets off looking for the spruce and dies off. Unfortunately, the rest of the adults are wingless and happily infest eastern American hemlocks. They lay eggs in mid-June, which hatch and attach to the hemlocks. These adults will over-winter and lay eggs the next spring. IDENTIFICATION OF INFECTED HEMLOCKS: Look for dessicated needles, turning gray-green and dropping off, and white, cottony masses on the undersides of twigs. BIOLOGICAL CONTROLS: There are no known effective native predators for the HWA, but there is a Japanese ladybug, Pseudoscymnus tsugae, which is very effective in Japan (helped by some natural resistance of Japanese hemlock species). The Connecticut Agricultural Experiment Station (CAES) is actively engaged in releasing large quantities of this beetle in various infested areas and results are encouraging. Future success will depend on whether enough Japanese ladybugs can be released to keep up with the HWA. FOREST MANAGEMENT: Without biological controls, the eastern hemlock forests are probably doomed. Spraying with pesticides is both prohibitively expensive and often not feasible because of terrain or proximity to streams. GARDEN AND NURSERY MANAGEMENT PHYSICAL MEANS: In a garden or nursery situation, It is often possible to control the HWA and save the hemlocks. The first step is to keep the HWA away discourage birds, squirrels and deer from coming near, and dont put feeders near the hemlocks. Also, keep any plant material from possibly infected areas away. Eggs and crawlers can be knocked off by wind and rain, so a good hosing periodically in spring and early summer can reduce an infestation. GARDEN AND NURSERY MANAGEMENT SUSCEPTIBILITY: Stressed trees are much more susceptible to damage, so its crucial to keep the trees healthy and well fed and watered. Drought stress in particular weakens the tree, as does planting in an inappropriate location. However, if the hemlock is severely infested already, dont fertilize with a high nitrogen fertilizer. This will only enhance the HWA growth. Wait until the infestation is under control before fertilizing. GARDEN AND NURSERY MANAGEMENT CHEMICAL MEANS: The first choice is to spray with horticultural oils or insecticidal soaps. These work by essentially suffocating the HWA, so you need to thorough coat the tree or the insects will survive. This can be difficult if the tree is very tall or inaccessible to spray equipment. Two sprays a year will probably be necessary, and expect to continue for a number of years until either the neighborhood is completely disinfected or other controls are available. The next choice is imidacloprid (Merit) which can be applied by stem injection or by soil drenching. The chemical is taken up by the tree systemically and will protect the tree for 5 months or more, but only if the tree has a healthy sap flow. If the tree is heavily infested, the sap wont flow and the pesticide never gets to the HWA. GARDEN AND NURSERY MANAGEMENT ALTERNATE SPECIES: You can also plant alternate hemlock species which are relatively resistant to HWA. Some American hemlocks from the west coast as well as Japanese hemlocks could be used.

It could already be dead. http://water.weather.gov/precip/  shows Indiana having above normal precip this summer. I'm guessing you have heavy clay soil and did not plant it on a mound to help shed excess rain. OTOH, this doesn't look quite like the firs I had die of my local root rot species...which has been a lot over the years...so I don't want to commit to a diagnosis. Mine tended to turn brown and hold their needles for a couple weeks. If it isn't quite dead and root rot is the problem, it's really too late for an anti-fungal to help it in the near term, but I (and others) have had some degree of success rescuing rhododendrons that were in rapid decline by irrigating with clean water with a 1/10 dilution of drugstore H202, this seems to rapidly kill off some of the problematic organisms although maybe not all of the ones involved. Then the next day, treat with a real anti-fungal if you are so inclined; but you probably need a professional one to fight Phytophthora at this point. I'm not sure any product at HD & Lowes is actually labeled for that and then you're asking yourself if spending $50+ to save a less expensive plant make sense, when you could always just start over. It isn't very big and that isn't a super rare species. You could always try Actinovate which, although it isn't labeled for many root rot organisms, I've heard some good reports about and which isn't too expensive.

I have had really good luck with S&S plants. I have made two orders (30 plants) and only had sudden needle drop one 1. It's actually very remarkable given the age of these plants. Fresh grafts like this are probably 10x more likely to croak without warning than a 1 year old graft. For those of us that do are own grafting, we know that the 1st year plants are at high risk. Sometimes there is an issue with the graft, but it only takes a small event to kill these plants that are still under stress from the grafting process. Then you factor in the stress of them being shipped, and 25% loss doesn't seem too bad.. especially given the wholesale price point. So the plants have always arrived in good condition, with the exception of 1. However, this plants are still at high risk for failure. I've probably lost about about 10/30 of the plants in those two orders. Most were my fault, I tried to overwinter them in my garage and it didn't go well, but I have also lost some that I planted directly in the ground. Of the ones that made it through their first winters, I don't think I lost any more after that though... they start to stabilize at that point. -Shawn