What’s killing my weigela - photo 1
It is not uncommon to see pretty ugly, tired and struggling leaves this time of year.
This doesn't usually doom the plant.
In the case of the hydrangea, they are susceptible to several leaf spot diseases, none of which are of huge concern or enough that you need to take action. We don't recommend any sprays as they are not curative.
They will flush out new healthy leaves next year.
More about that here: https://www.uaex.edu/publications/pdf/FSA-7570.pdf
Weigela can get the same leaf spot and no treatment is needed as noted above.
They can also get foliar nematodes, but that is less likely.
Foliar disease loads can vary year to year, being worse in wet, rainy years and under crowded conditions where lack of airflow allows leaves to stay wet longer. Sanitation, i.e. raking and disposing of diseased leaves can lessen the pathogens around for next season.