Q: We live on a shady lot and have a lot of aucuba plants around our small lawn. Some of the aucuba have leaves that are turning black and wilting. Does this mean they are dying?
A: If it makes you feel any better, some of my aucubas are doing the same thing. They are suffering from Phytophthora root rot, a soil disease that commonly affects azalea, rhododendron and aucuba shrubs.
The fungus itself is present in most soils. There is no way to eliminate it.
It attacks susceptible plants when they become vulnerable due to drought stress, winter injury to stems or compacted clay soil. The disease works its way up from ground level; little can be done once a plant is affected except removing wilted branches.
Nonetheless, a healthy plant in the correct environment can keep the disease at bay. I plan to remove mine, thoroughly amend the soil and plant more in the same spot.