Hello Caitlin, 

     Yes, You may need to reduce the amount of water to the plant. You may also have mites or aphids . 

     Is the location sunny  or shady , and how much sun or shade is it getting?  Is the soil heavy or does it drain well? 

 When watering water from the base of the plant and keep the leave dry. If that is not possible water early in the day to allow enough time for the leaves to dry before evening. The soil should be moist not wet. 

 For the "white powder" it could be aphids, try just brushing the powder off and keep the ground around the plant clear of leaf fodder or heavy mulch.  If that doesn't help you may need to use neem oil or insecticidal soap. Try brushing with your fingers first before using insecticide, it may be easier on the plant.

Hello Caitlin,

     I am including a short tips link for your Hydrangea. It will help with some of the care. 

     If possible could you send a couple pictures of the complete plant so I may see how much of it is effected? It is not unusual for plants to lose some lower leaves on newer planting as long as the newer upper leaves appear healthy.

https://www.provenwinners.com/plants/hydrangea/bobo-panicle-hydrangea-hydrangea-paniculata

https://extension.oregonstate.edu/gardening/flowers-shrubs-trees/general-care-hydrangeas

Hello Caitlin,

     After seeing the complete plant I do not think you have anything to be concerned about. When you get a chance review the links I sent with the last message . Follow the suggestions for watering and fertilizing, dispose of the leaves as they drop to prevent fungal infection and a little mulch goes a long way. Some mulch will help keep the soil moist and the roots cooler on the hot days ahead.  

     Enjoy your hydrangea!!