...where the existing soil was very hard packed and poorly drained. By the time I was done planting I was so excited about how many neat things I could grow there, that I kind of forgot why I'd made the raised bed to begin with. When I looked at the finished product I thought, "Now all it needs is a nice border."
I knew yew makes a great low hedge, so that's what I planted to outline my masterpiece.
Within a few weeks I saw my mistake. The yews yellowed and failed. They weren't on the bed above the wet but right in a gutter, where the water would drain off the berm and pool on top of the poorly drained original soil.
I know yews don't like wet so why did I plant them in a space bound to be soggy?!
Like a canary in the coal mine they'll be the first ones to keel over and die when the environment changes. Just as miners can't see the gas that might kill them, we can't see that excess water in the eighteen inch depth where most roots grow. So test for it and plant to suit existing drainage. For more about drainage and how to test for it, check What's Coming Up #15.