Planting taxus densiformis yews
We're planning to pulling out six sick yews and planting new ones. They have struggled for over ten years unlike the yews immediately adjacent. They were yellow, had few needles and hardly grew. They are located next to a stone wall and I suspect masonry debris remains in the ground, which we will try to find and remove. Our base soil is mostly clay. What might be the best combination of soil mix to use? I have heard several different recommendations, but I'm leaning toward 1/3 existing, 1/3 sand and 1/3 topsoil, gravel and canadian peat. Also, I'm planning to make sure there is a little slope to try to avoid poor drainage.
Livingston County Michigan
The Densiformis yew (Taxus xmedia ‘Densiformis’) is an evergreen shrub that prefers acid to neutral, fertile soil, possibly on the sandy side. It requires sufficient moisture but must have excellent drainage. Poor drainage can be the death of a yew. Because you are having a problem with the site of the shrubs, I suggest that you have the soil analyzed before you replace the yews. You can obtain a soil test kit at: https://homesoiltest.msu.edu/get-started The results will explain the content of your soil and the best way to amend it so the yews will grow.
Since sufficient moisture and good drainage is of paramount importance for a healthy yew, you can assess the water infiltration rate of the soil by doing a soil percolation test. To learn how, go to https://www.canr.msu.edu/news/determining_soil_infiltration_rate .
In this way, you can prepare the soil for healthy yews.
Thank you for your question.