When I first began planning my Serenity Garden, I was inspired by a secluded woodland-edge area, dominated by two large white pine trees (Pinus strobus), that sat at the back of a mossy clearing behind my house. The clearing was surrounded on three sides by woods, and I had begun to enclose the fourth side by planting a line of shrubs to separate the quiet mossy clearing from my clothesline area. By the time I was ready to make the Serenity Garden a reality, however, the nature of my clearing had changed dramatically. The septic system leaching field beneath the clearing failed, and the whole area had to be excavated for the installation of a new leaching field. When the new septic system was completed, my line of shrubs had been removed and the secluded mossy clearing had been transformed into a wide open grassy swath. (See My Not-So-Secret Garden.) The problem that then presented itself was how to recreate a sense of seclusion without plantings that would send roots down into the leaching field.
The new woodland garden (the Serenity Garden) has been in place for two years now. After looking into possibilities and considering the suggestions from my wonderful garden blogging community, I decided to recreate the sense of enclosure I originally envisioned by using a large raised bed (essentially a 4’ x 12’ planter) to close off the fourth side of the (now larger and grassy) clearing and to separate it both physically and visually from the clothesline area.
In order to create the raised bed, I used raised bed corner brackets from Gardener’s Supply Company and 5/4” x 6” white cedar decking planks. The corner brackets are designed to hold 2 x 6 boards, but I did not want to use pressure-treated lumber and rot-resistant white cedar dimensional lumber is not readily available in my area and is prohibitively expensive. Instead, I used pieces of exterior vinyl trim to shim the 5/4” planks so that they fit snugly in the corner brackets. Gardener’s Supply does not recommend using their corner brackets to connect boards longer than 8’ and I was using 12’ planks on the long sides, so I cut a couple of lengths of 1/2” diameter PVC pipe, sunk them a few inches into the ground and strapped them to the center of the cedar planks to stabilize them. Here you can see the progress of the raised bed as it was constructed:
Once the raised bed frame was finished, I covered the bottom with cardboard to smother the sod and then filled it with a mixture of loam left over from the leaching field project, inexpensive bagged topsoil, compost, and composted cow manure.
This raised bed is intended to create both a physical and a visual barrier between the Serenity Garden and the clothesline area (and the driveway beyond). The physical 4’ x 12’ cedar structure creates an effective physical barrier; although it is possible to squeeze by it, the only obvious entrance into the quiet clearing is now through this narrow neck between the Blue and Yellow Border and the Fence Border, which effectively creates a strong sense of entering a separate garden “room.”
The raised bed structure is not large enough, however, to provide a visual barrier; for that, it needs architectural plants that have visual mass and will call attention to themselves. At the same time, though, I don’t want large flashy blooms for this planting; it needs to share the Serenity Garden’s emphasis on foliage. With these considerations in mind, I decided on a combination of amsonia (blue star flower) and hardy geraniums.
The focal center is three Amsonia hubrichtii. If these behave like the amsonia that I planted in the Blue and Yellow Border 10 years ago, they will grow to a height of about 3 1/2’ (4 1/2 – 5’ once you add the height of the raised bed) and a diameter of more than 4’ at their crowns, and they will provide a mass of attractive foliage from spring through fall. The smaller Amsonia x ‘Blue Ice’ plants provide lower-growing foliage for the edges of the planting and prominent blue flowers in early summer when the raised bed will be in bloom. The plants of Geranium x oxonianum will provide a contrasting foliage shape and texture, and its pink flowers will drape themselves over the foliage of the large plants behind them in a charming way. On the back side of the raised bed (facing the clothesline and driveway), Geranium x cantabrigiense ‘Biokovo’ is a low-growing groundcover that will fill in the spaces between other plants, spill over the sides of the planter, add a mass of quietly lovely flowers to the mix in early summer, provide attractive foliage throughout the garden season, and visually tie this planting to other nearby flower beds (the Deck Border, the Fence Border, and the Serenity Garden) that also have Geranium x cantabrigiense growing along their front edges.
Right now, the newly planted raised bed looks a bit sparse and scraggly. My hope is that, within a few years, it will fulfill my vision of lovely closure for the Serenity Garden project.