Berberis is an invasive species introduced to North America from Asia.  As of 2014, it has been added to the Invasive Species list and is not longer available to sell.  

Although there is no true substitute for Berberis, here are some suggested alternatives:

Boxwood blight, recently found in the U.S, is a serious disease affecting all boxwood with uncertain long term implications.  We urge the landscape  professional to use aggressive measures to control this disease. 

Although there is no true substitute for the boxwood, here are some suggested alternatives:

Impatiens walleriana, once the king of shade-loving annuals, has been seriously challenged by downy mildew. There are a few varieties of impatiens which are either immune or do not show the disease as strongly as I. walleriana.  Here is a list:

Note: New Guinea Impatiens have been touted as a 'sun' plant, but they will work very well in the shade.