We are in the midst of some new construction, and need to put in some stormwater controls around our building and parking areas. I have been hearing a lot about rain gardens, which could be a solution because it would provide stormwater control and be our landscaping. But the more I think about it, it seems like the maintenance work and costs could be prohibitive (weeding, mulching, etc.), and that maybe a bioretention swale would be the better (but less attractive) option. Has anyone put in a rain garden on their properties or have an idea of how much expense is involved in their construction and/or maintenance? Thanks!

Unfortunately, I do not have direct experience with rain gardens.  However, I recently came across the following webpage http://www.werf.org/livablecommunities/index.htm  which offers some resources.  If you browse the case studies for Kansas City, MO, you may be able to contact someone in their 10,000 Rain Garden Initiative for information that can answer your questions.