Hello, Kristin. Looks like Cercospora leaf spot and, ugh, a bad & early infestation at that. It normally starts later in the summer and at the bottom of the shrub & spreads up. Damaged areas are brownish with sometimes a purple halo. Anthracnose is a darker shade of brown; see the links below.

If you have not already tried doing these things, try some "clean sanitation" / "good housekeeping" practices: no overhead watering (water only the soil and do so early in the mornings); discard the leaves in the trash when the plant goes dormant; replace the mulch with heavy infestations; discard any plant debris at the bottom of the plant; improve wind flow by not planting other shrubs very close to the infected plant; prune early those leaves that are about to fall, that are very infected (biggest leaf pic #1), that have areas that appear to be disintegrating (leaf to the left of the biggest leaf in pic #1). The infestation will make some leaves turn yellowish after a while... at which point I sometimes prune those too.

Frequent summer rains can increase the rate of the spread of this disease, the leaf spotting and the defoliation (which is why you should prune off early the worst leaves). Watering the soil only, not over-watering and drought conditions help reduce/slow the spread.

The down spout may be helping the infestation in this case too so see if you can deflect the water away from the plant. If all this is too difficult to control the disease and you can afford replacing the shrub it, consider replacing the shrub.

For control with a fungicide, begin applications when spotting of the leaves is first seen and continue applying per label directions. Fungicides registered for the control of Cercospora leaf spot: azoxystrobin (aka Heritage; has the smallest application rate and largest repeat interval); chlorothalonil (Daconil); mancozeb (Dithane; Protect; etc); myclobutanil (Immunox); thiophanate-methyl (Cleary's 3336). Note that these fungicides try to control the spread but do not cure and cannot prevent the symptoms from re-infestation in future years. They work best when you apply fungicides with different active ingredients. For example: start with active ingredient #1; if it is good for 7 days then on the 7th day, spray with active ingredient #2; if that one is good for 14 days then on the 14th day, go back to spraying active ingredient #1; and so forth.

Some of my shrubs have this problem but the leaf spots show up later, like in late August or September (we have hardly any rain in July-August so that helps me). More info:

http://www.aces.edu/pubs/docs/A/ANR-1212/ANR-1212.pdf

or

https://clemson.edu/extension/hgic/plants/landscape/shrubs/hgic1067.html

Luis, thank you for the thorough and thoughtful response. I immunoxed again yesterday after cutting off every. Single. Infected leaf. They are pretty far apart- about 2.5 feet each and I water with a drip hose. Le sigh. I think I just got bad luck this time. Thanks for the info about rotating active ingredients. I will try that. Ugh why does gardening have to be such a crapshoot?!

I live in southwest Louisiana and we did just have two weeks of lots and lots if rain.