This is an American holly. These get very unruly when they’re overgrown. The stems go all over the place, sideways and downward and when you start pruning them it can be confusing what to do. So this is often where it ends up.😂✂️ As you can see, it bounces back very quickly. Japanese hollis are similarly fast growing.Apply this same approach to any overgrown shrub if you’re impatient to do it in stages. If you’re asking for the “best” time, it’s late winter/early spring but we tend to like to s