I have a well established (5yrs old) Elderberry, (Sambucus Nigra Guicho Purple) that appears to have verticillium wilt (leaves wilt and die on branches). Pruning the diseased wood seemed to force the wilt to progress quickly to other branches. Leaving the dead branches slowed the wilt and new growth was appearing seemingly unaffected. Now, neighbouring shrubs, (Sambucus Plumosa Aurea), have a scorched appearance on its leaves as well half of a Chokeberry, (Aronia Autumn Magic) leaves have turned prematurely red and its fruit is withered before it ripens. These shrubs have always been healthy until this Spring when I noticed the sparce and wilted leaves on the Sambucus. In early spring (before I was aware of a problem) I transplanted creeping jenny from around the Sambucus to a location that is in close proximity to a Catalpa tree. Have I just spread this disease to the Catalpa tree, which is susceptible to verticillium wilt? Should I remove and destroy all three shrubs now? How far can this disease spread? Is this disease brought on by drought? We have been unusally dry for the past two growing seasons on Vancouver Island. Any tips on the prevention of the spread of this disease would be greatly appreciated.