We think that this plant looks like it may be veronica.  The yellow foliage looks like there may be too much moisture in the area.  Check the drainage and make sure mulch is no thicker than several inches and away from the base of the stems.  We notice new growth and that is a good sign.  No other controls are recommended now. Rake and discard any fallen foliage. 
Monitor the growth and health of the plant and if you notice additional symptoms, send us more photos so we can see what you may be dealing with. 

Marian

thanks so much.  Will keep an eye on it and check on drainage.  I have turned up the drip system time this year as I have so many perennials in that bed.  Yes, Veronica sounds right!

You're welcome.