Having problems with a yew hedge. Most of them are healthy but a few have died and been replaced, and two others are dead/dying. Seeking advice from gardeners and garden shops - getting different suggestions: overwatered, underwatered, root rot, fungal attack….. I doubt the problem is watering - most of the hedge is thriving. So it's got to be something else, but what? And how to get a precise diagnosis and prescribed treatment. Help!
Varying damage within a planting does not exclude root rot as a possibility. Yew (Taxus spp.)-Root Rot
If that is the case, and Phytophthora sp. is to blame, how do I confirm it and treat it? Or is there a general treatment that would cover more possibilities?
Regardless of Phytophthora, Armilaaria or not, hygiene is your priority. Is Armillaria (honey fungus) in your area? (bunches of yellow mushrooms are usually present late summer into autumn (here in australia that is) Root diseases often occur from prolonged wet periods followed by drought. The wet encourages disease to flourish and the drought weakens the plant to succumb. 1. Carefully remove the mulch and any soil that is above the root flare. 2. Dispose of this material. 3. UBC may have pathology services that provide pathogen testing. 4. It looks like you're going to lose a couple more to whatever it is. 5. Most soil-borne diseases are quite contagious so avoid walking along the hedge. 6. Laying old carpet around the infected site while dealing with the diseased plants works well to keep your boots clean and reduces water movement 7. Don't shred or compost the dead plant material. Don't put it in your recycling bin. Do burn it or landfill 8 Clean your pruning tools with bleach or methylated spirit 9 Clean your digging tools with bleach 10 Improve the health of the surrounding hedge 11. You need to increase the biological activity in the soil. Chicken manure, thoroughly composted material followed by soft wooded mulch will encourage beneficials. 12. Water deeply but infrequently. 13. There's no cure for "P" . Sanitation, Hygiene and prevention are the best approach.
I'm sorry Avid One more suggestion is to spray the surrounding hedge and plants with Phosphonic acid 600g/l . We use it as a preventative application for Phytopthora It won't help the infected plants Here's some info Understanding the Phosphonate Products
