Our featured project is a residence located on the Wye River, in Queenstown, on the Eastern Shore of Maryland.
Architectural Gardens met with the clients in the summer of 2011 to plan a sustainable landscape design that would work with a newly-installed heavy Armor Stone Revetment on the client’s shoreline which consists of northern and eastern facing slopes. The design was to also incorporate the existing large oak trees located on the property. Pictured below is a “before” photograph of the eastern slope with the oak trees. This is the steeper of the two slopes at a 60% grade.
The northern slope has a 45% grade and both slopes have sandy soil and are subject to high winds. When the stone revetment was completed, annual rye grass was sown for erosion control. There are multiple causes for erosion on the site—storms, water current and water run-off due to the existing grades. Here is a view of the existing northern slope.
Architectural Gardens met with the clients to plan the initial phase of the multi-phase project in September 2011. A fall planting was commenced on the extensive northern and eastern shoreline. To give the reader an idea of what was entailed in this phase, over 300 trees and shrubs were planted along with 2,000 plugs of liriope for ground cover. A summary of the anticipated phases of the plan are: The first phase would initially fill in the sloped area with small trees and shrubs–leaving room for paths for maintenance tasks; in the next phase, perennials and grasses would be added to complete the picture; finally, the erosion of the property at the top of the slope would need to be addressed with the use of a combination of possible solutions including bio-retention, terracing and rainscaping. Below are more views of the existing grade and slope of the site.
The goal of the overall plan is to achieve year-round interest with a balance of evergreen and deciduous trees and shrubs; most importantly, the plants utilized would need to be proven successful in the conditions presented at this site. The homeowner wanted to use native plants, where possible, for their ecological and wildlife value. Plantings would have to run the gamut of moisture tolerance at the toe of the slope and drought and wind tolerance on the top side—in addition to the existence of root competition and summer shade from the oaks. This featured project is a good example of creating a fluid plan to be completed in stages that not only meets budgetary constraints but can also evolve in its later phases.
Phase I – Phase I initiated the plantings on the slopes and was completed in October, 2011. This phase included both the northern and the eastern slope of the property.
Northern Slope Details
Starting at the bottom of slope, Itea virginica (Virginia sweetspire) was planted. It is a native shrub that is deciduous with fragrant spring flowers and a brilliant red fall color. For a taller focal point, another native was planted–Aronia (chokeberry), which displays spring flowers, fall color and berries for winter interest. The bottom of the slope was also planted with Lespedeza, which aids in erosion control and sports rosy purple flowers in August through September. It has a mounding habit and bluish-green foliage.
Mid-slope is planted with another native, Inkberry holly– an evergreen that provides winter interest, wildlife value, and tolerates moist conditions with good drainage. Calycanthus (Sweetshrub, Carolina Allspice), another deciduous, fragrant native shrub with fruit which persists through the winter, was planted near the steps to the beach.
At the top of the slope, Holger junipers (evergreen, drought-tolerant), Bearberry cotoneaster (evergreen low-growing ground cover with prostrate branches and spreading habit), and shrub roses (Meidland Red, low-growing, spreading habit with color for three seasons) were planted.
Above is a closer view of the northern slope, as planted. The northern slope’s grade is more moderate than the eastern slope and you can see the extent of the shoreline and the amount of plants necessary to create the shoreline landscape.
Eastern Slope Details
Liriope spicata (evergreen) was planted for a low-maintenance ground cover that has flowers and berries, along with spreading Gro-lo Sumac which is a cultivated variety of our native fragrant sumac that thrives in harsh settings. It is perfect for the windy, less-than-ideal conditions of the coast. Pictured are closer views of the eastern slope, as planted. Note the steepness of the eastern slope in the first view.
Here is a view of the planted eastern slope from the pier.
Phase II – Phase II will add ornamental grasses and perennials to the mix of plantings on the slopes to fill in, to aid in erosion control, and add more variety to the plantings.
Phase III – Phase III will balance and raise the grade of the lawn where run-off is creating extreme erosion issues. River cobble, stepping stones, terracing and rainscaping will all be incorporated to aid in bio-retention—slowing water run-off down and filtering it before it reaches the river. Below is a couple of views of the grade and flow of water from the upper part of the property to the river. This is the area that will need to be addressed in Phase III.
To control the erosion, slow the water down and filter it, a shallow pit (18”-24” depth x 15’-18’ diameter) must be excavated above the slope (where water can be collected from the lawn uphill) and sited so that there is no harm done to the existing tree roots. The area will then be covered with a filter cloth membrane and backfilled to 2/3 of its depth with 1”-2” clean gravel.
For aesthetic purposes, the top of the pit area will be covered with small/medium (1-3”) river cobble and path stones to provide egress through the area. Because the flow of water is heavily concentrated in this part of the yard, a swale sandwiched between the waterfront slope, house foundation and pool grade will lead to the pit. Beyond the collection pit will be a series of steps consisting of timber treads. Between each step will be a 4-6” of gravel backfill on filter cloth. This technique slows the water flow, forcing it to cascade down each step. This will control erosion and protect the beach area at the shoreline below. Again, for aesthetics, the gravel will be covered with river cobble.
We are anxious to see how this landscape flourishes over time. With a fall planting, the new plants are not at their peak and can look rather sparse but fall is a good time to plant and get roots established. The key to success is to plant at the ideal time and get through the first year or two.
The homeowners stated that they were “very pleased” with the initial work and thought that Phase I was “a job well done.”