Answer: The most common causes are dog urine and water stress. Excess water (or poorly draining soils) can cause dieback in yews. Even though the weather has been hot, the yews will still get by with one-inch of water per week. Excessive watering can exclude oxygen from the soil which can suffocate the roots. It will be much better for your yews if you dig a water well or watering basin beneath each and flood the basin once each week. If the weather is really hot you can flood the basin, allow it to drain, then flood it a second time. This method of watering concentrates the moisture over the rootmass and allows it to trickle down, wetting then entire root mass. Wait 3-4 days, then dig down into the soil. If it is still moist 3" beneath the surface, you won't need to water for another 3-4 days; if it is dry, it is time to water. Best wishes with your landscape.
Q&A Library Searching Tips