Mandeville Causeway Interchange


Our firm has produced plans for a beautification of the open space at the intersection of East Causeway Approach and US Hwy-190.

Much of St Tammany Parish was once covered by Longleaf pine savannah, prior to the arrival of the industrial logging industry.  The dense, resinous wood of these trees made them attractive to commercial loggers, but also affords a natural protection against the Pinebark Beetles which have lately plagued our area.

An overall concept was established early in the design process.  By reestablishing a landscape based on the area’s native ecosystem, a native-plant community will be introduced which requires minimal maintenance and upkeep.  The Longleaf Pine Savannah proposed to fill this area was chosen for several reasons:

The stratified nature of a pine savannah provides dense vegetation up to height of about three feet, and tree canopies higher above, this will maintain the essential line of sight between passing cars and existing businesses.

Minimal maintenance requirements (via a reduction of turfgrass mowing area, the wildflower area will require cutting only once per year).

No irrigation will be required in the “native” portion of the design, but will be provided to establish the health of the Live Oaks around the perimeter of the site.

The nature of a local Pine Savannah is a community of very few species of trees (in our case, Longleaf Pine, Live Oaks, and Red Oaks), with myriad flowers and grasses proliferating below.  This project will provide over a hundred species of these smaller plant species.  This understory planting mix will be seen to undergo a transformative process in the first few years, as the native plants out-compete any weed establishment.  In lieu of the natural yearly burn cycle the local landscape originally thrived in, a once-per-year cutback of the wildflower area will be the only long term maintenance commitment.

Once established, this wildflower area will provide an appropriate beautification for drivers to enjoy at traveling speed, while actually easing the maintenance burden on the City.