Thank you so much for getting back to me! When the yew was planted there wasn’t any new soil introduced. My question is, can I now dig maybe a 3 ft. trough around it introducing as you recommended compost and perlite? Even though I have the guarantee from the nursery I would still like to save it! I have backed off on the watering and there is new growth so that is a plus..
It sounds as if your yew is doing well now, which is good news. If you take a close look at the advice in the last post about introducing compost, it does not mention digging a trench, but rather “turning the soil” to add the compost. Here’s the previous response ( https://www.torontomastergardeners.ca/index.php/askagardener/hicks-yew/) in its entirety:
Yews grow equally well in full sun or shade and your site looks to be sheltered. The most likely cause of yellowing needles on a Hicks yew (Taxus x media “Hicksii”) is a drainage problem. Since this is a recently been planted yew perhaps you are watering it too much. Yew shrubs do not like standing in water. Wet, soggy soil leads to root decomposition and eventually death in all yew shrubs. Water that sits in the soil depletes the soil of oxygen, damaging the roots. With the roots damaged, the proper amounts of nutrients fail to reach the plant, leading to foliage damage in the form of yellow discoloration. Drainage problems are most prevalent in clay soils that are too compacted. Turning the soil, adding 3 to 4 inches of compost or introducing soil amendments, such as peat moss and perlite, will help break up the soil and promote better drainage. Lack of water can also cause problems. Make sure you water in very dry periods and water before the ground freezes in winter.
If the ends of the branches show signs of growth all is well. To remove the yellow needles because they are unsightly just shake the branches and they will drop off. Remove them from the ground.
Good luck with your new yew!