Webs on Shrubs
The pictured webs on my yews are similar to tent caterpillar but not so dense. Also, no caterpillars. Also on a few azaleas. Yew's needles got yellow and dropped off. The pictured yew is about 7 feet tall with a diameter of 4 feet. What are they and how to get rid of them please.
Your photo was not in focus but the webbing looks like spider webs. They are not harming your shrubs. Spiders are predators and help keep pest insects in check.
We really do not have enough information to answer your question. You can send us digital photos of the (yew) shrub and around the base of the shrub.
Yews do not get a lot of insect and disease issues. May be a root problem. Yews in general do not like wet feet and grow best in well drained soil. Heavy clay soils and poor drainage can cause decline. Look for downspouts and any drainage issues in the area. If so, you will need to correct this. It is possible the yew may not be able to recover.