I don't find any woody stemmed shrubs on lists of plants that may be hosts to, or susceptible to, Sclerotium rolfsii - fungal crown rot of hostas and daylily. The list appears to only contain herbaceous perennial plants.

Is the drainage in your bed adequate? Phytophthora is normally found in poorly draining, overly moist planting sites.

Thanks, morz8, for the info. The bed is naturally on the dry side and would be very dry if I didn't water when needed. Sounds like it will be safe for the Purple Gem. My soil is very sandy so I have to augment the planting hole with a mixture that will hold some moisture.

There are also phytophthora problems during a drought. When a drought weakens a plant, is it common for phytophthora dieback [Phytophthora cactorum] to infect the drought stricken plants. It attacks the branches. It usually take entire branches.

Phytophthora root rot [Phytophthora cinnamomi] usually kills the entire plant. It attacks the roots.

My point is, you need moist well drained soil. Too dry is bad and too wet is bad.