Answer: In this age of drought tolerant plants and water conservation, what you describe sounds like an unusual growing situation, but it's really quite common in some of the more established housing developments, especially near downtown Mesa. All yards there are irrigated by flooding and berms were actually built into the yards to hold the irrigation water. In fact, most of the established citrus groves are watered in exactly the same way. So, take advantage of the situation and enjoy a lush, green landscape.
Even though the soil is acidic and moisture abundant, ferns might still struggle because of the dry air inherent to the desert. You might try a single plant to see if evaporation of the residual water will provide enough humidity to make it happy. Summerwinds Nursery has a nice selection of ferns. Ornamental grasses typically like full sun exposure and there are many to choose from. Japanese Bloodgrass is very popular, as is Oat grass and Rattlesnake grass. Again, Summerwinds is a great place to visit, admire plants, and choose those that appeal to you. The staff there is quite helpful.
Best wishes with your landscape!
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