Thank you for your question, Bess. We cannot diagnose plant problems without clear photos taken from close to the leaves, and often an examination is required. There are both diseases (https://extension.psu.edu/home-fruit-plantings-elderberry-disease-descriptions) and insects (borers) which can harm the plant. Have you examined the leaves and bark for these issues? If this is a disease, the best resource for getting an answer would be to submit tissue and soil samples to the OSU Plant Clinic: https://bpp.oregonstate.edu/plant-clinic One other thought is that the soil pH is not acidic enough, as it should be between 5.5 and 6.5. (https://extension.psu.edu/home-fruit-plantings-elderberries). Again, this requires a simple test. But, I am uncertain how much effort you want to expend tracking down the problem(s). Good luck!