Thank you for contacting Ask Extension. In looking at the pictures that you sent, I can see two problems with your barberry. The first is that it has powdery mildew, which is a fungal disease that appears like white dust on the leaves. You can use a fungicide for powdery mildew, or you can use Neem oil. Either way, follow the instructions on the label and do not spray them until evening, so as not to burn the leaves. The second problem is the drip irrigation hoses. Barberry does not like to be in wet soils, which is where the powdery mildew probably came from. I would suggest moving the hoses out, or moving the plants.

I did include a publication on the invasiveness of Japanese barberry. It is on the Midwest Invasive Species List (MISIN.msu.edu). So if you decide to replace them, you might want to consider a non-invasive shrub, such as ninebark (in many colors), chokeberry or an evergreen, such as threadlike junipers.

https://ipm.cahnr.uconn.edu/invasive_plants_japanese_barberry/

https://hgic.clemson.edu/factsheet/barberry/ - :~:text=Barberries%20prefer%20sun%20or%20partial%20shade.%20They%20are,done%20immediately%20after%20flowering%20or%20in%20later%20winter.