There are a few ways to know if your Blue Spruce is not doing very well. You could notice their needles turning yellow or brown and even drop off. This is a sign that your tree might be diseased and should receive immediate attention. Your plant could also be suffering from drying shoots, both new shoots, and lower branches. This issue is caused by a type of fungal disease. You can conduct an at-home test to see if your plant is diseased or not. However, we suggest contacting a local arborist for their professional opinion and plan of attack.