phytopthora crown rot
I am ready to plant in areas where I believe phytopthora has recently killed my rhododendron. Do I need to dig out and discard the soil before putting in new plants? My new plants are supposed to be resistant to the fungus. (Calycanthus)
Yes, unfortunately digging out the site and replacing as much of the soil as possible is the best action with phytopthora. It can remain in infected soil for many years. Make sure the bed is well drained, if time allows, now is the perfect time to raise the bed. Resistant varieties should be selected and the calycarpus is a nice choice.
Feel free to contact our office if you have other questions.
Let me know if I can help you further!
Jefferson County Cooperative Extension Service
810 Barret Ave
Louisville KY 40204