Taxus species of evergreen shrubs are frequent submissions in the plant pest lab. Scroll to learn more about common problems we see contributing to yew decline.

To reduce the risk of decline, stress, pests, and diseases on yew it is important to select a suitable site for yew and ensure the soil area is well-drained. For more details about ideal growing conditions for yew please visit this helpful resource from NC State Extension.

Edema

Yews are very sensitive to waterlogged soils. When the roots are sitting too long in saturated soils that are not draining, we can see evidence of this on the needles. The undersides of the needles will produce corky, raised bumps as a result of cells that have burst from too much water. Ensuring soil is well-drained can help reduce plant stress and edema in yew.

Root rot

Always check the roots of a plant before planting! This yew tested positive for phytophthora root rot, and also had much of its root system cut before planting. The soil on the sample was a heavy clay, making water drainage difficult and conditions for root rot ideal. The soil was covering some of the lower stem, indicating the yew was planted too deep. Root rots can cause dieback in the above ground part of plants and eventually plant death.

There are other environmental conditions that can cause yellowing and browning in yews. Dramatic changes in winter temperatures can cause stress. Salt applied to icy roads and sidewalks can cause browning if applied close to yews. Damage to stems can leave wounds on yews that leave them susceptible to fungal canker pathogens.

With all plants, what is important to avoid plant disease and plant pests is planting the right plant in the right place. Ensure you plant your yews in well-drained soil, check root health before planting, and you will have a hardy and lovely evergreen shrub for many years to come!

Yews showing signs of stress from overwatering.

Container yews experiencing phytophthora root rot.

Images of declining yews in different planting situations. Left image yews are suffering from overwatering and poorly drained soils, right images yews tested positive for phytophthora root rot. Plants cannot be diagnosed by images alone! Photos courtesy of Alan Windham.