Spider webs become very noticeable when morning dew highlights them and when they build up because heavy rain has not washed them away for a long time. Spiders are beneficial to your boxwoods, however, because they feed on problem insects. Don't spray any pesticide on them. If you dislike all the webs, you can brush them off gently with a broom. Also, you should water your boxwoods deeply if you do not get good soaking rains before the ground freezes.