Originally Posted by brown thumb
I would go clear back and look at the species planted. Plant native plants and grasses or at least cultivars selected for the specific micro-climate in which they are planted. Native prairie plants and native grasses are extremely tough and require little attention to get established.
Good lord Brown,
If I went into this commercial business and advocated they take up all the plants and make the original designer appear to be ignorant, they would open up the door and escort me out.
The original design could work dependent upon certain factors. Mostly, water budgeting, monitoring water outputs, and proper drainage. Sometimes, you can't correct other designers mistakes as you know it is easier to draw a landscape design and sell it. It is harder to make it come out in dirt. The obstacles you encounter from local suppliers often makes things change. However, if the design wasn't installed correctly, then something needs to be done with it.
I know these things are touchy with clients whom use big name local landscape companies. If you post bad images of this company, the customer only looks at you as a problem maker.
Problems will occur from out of state contractor's doing shoddy work and not caring about local support. In such cases, it may be beneficial, but I haven't been too lucky in the pointing fingers department.
I think the op can handle this like a new born and slowly win the confidence of the business and make slight changes rather than do it all at once.