Gardening for a Purpose

Marann Jones
Adam's County Master Gardener Program

(11/1) Some people want a garden that is functional, while others want a garden that exists purely for aesthetic beauty. For many, however, the joy of gardening comes to life when their purpose is both aesthetic and functional. So how do we marry the two?

You may have a concern about a drainage or storm water problem on your property. Maybe you are not happy with the way the water flows from the farmerís field, dumping pesticides and fertilizers on your property. You may also scratch your head about water from your downspouts rolling across your newly treated lawn. Perhaps you worry about the environment and want to do your part to protect nearby lakes, rivers, bays and streams from pollutants.

These problems beg for a solution. So, I shall now put on my Master Gardener cap and suggest that you design a filtration strip or a rain garden using plants to solve your water pollutant problem. Letís define both options.

A filtration strip is a gentle slope of land Ė about 10 % gradeĖ on which you grow native plants and grasses. These natives act as a barrier for surface water runoff at the edge of a hard-surfaced area or a stream. They act like a sponge to clean and filter the water before it enters waterways. A rain garden on the other hand, is more than just a strip planted to filter storm water. It is designed as a bio-retention area that acts as a natural storm water pollutant solution. It is functional and environmentally friendly while lessening the amount of flooding in the area. It is also aesthetically pleasing to the eye.

As you weigh whether to use a filtration strip versus a rain garden for your runoff problem, start by doing a thorough site analysis along with a soil test. This will help you to decide whether to design a rain garden or a filtration strip, specific plants to use and the size of the garden. Soil testing gives you an idea of your areaís composition and whether the soil needs amended by replacement and addition of sand, topsoil and compost to improve percolation. Make sure to set your water runoff garden at least 10ft away from the house to prevent damage to the foundation.

Your next step will be to design the garden on paper. Will it be a rain garden or filtration strip? For either garden style you will want to choose native plants because they have elaborate root systems that create channels into the soil causing it to more readily absorb water.

This is how we dealt with our own runoff problem. First we located the source of the runoff - a farmerís field - then took some elevations for slope accuracy, and marked out the designated area. We dug a pit three feet deep. Our site analysis came in handy because we came across utilities lines which required a call to the utility provider to come out and mark them. When we came close to the marked spots, we dug under the lines by hand to be safe rather than sorry and ran our perforated drain pipe under them. We lined the area underneath with stones to prevent erosion. When all the piping was installed, we filled in the rest of the trench with excavated soil and a mixture of 50 percent sand, 30 percent compost and 10 percent topsoil. Next, we created a very flat bottom to allow the water to evenly percolate downward.

After all the ground prepping was done, we were now ready to plant. Rain gardens have three zones. In zone one, the ponding area. I used plants that can tolerate standing and fluctuating water levels. It is the lowest area where the runoff enters the garden. I planted winter holly (Ilex verticillata) which is a beautiful deciduous holly bush that is a native plant. It is the only holly that I know of that loses it leaves in the winter. They have a stunning fall color and their berries are not only attractive, but make a good meal for the birds. I also used Red-osier dogwood (Cornus serica stolonifera), Cardinal flower (Lobialia cardinalis), and New York ironweed (Veronia noveboracensis).

Zone two is known as the middle area. This area is slightly drier so I used plants that can tolerate fluctuating water levels, but not standing water. I planted Spiderwort (Tradescantia virginica), Great blue lobelia (L.siphilitica), Wild columbine (Aquilegia canadensis) Black-eye Susan (Rudbeckia fulgida).

The third zone is referred to as the berm. It is the driest part of the garden. It can be planted with grass or ground cover that can tolerate drought. For this third zone I planted native ground cover to meet the existing grass edge. Some of the plants I chose were Creeping phlox (Phlox stolonifera), Moss phlox (Phlox subulata),Woodland stonedrop (Sedum ternatum). Of course, there are many more native plants to choose from, and I have only listed a few. Suggestion: consult your local extension office for a list of native plants that will thrive while absorbing excess water runoff.

Now that the garden is all planted up and a little bit of mulch is added for aesthetics, it is not over just yet. Maintain it by doing a tad bit of weeding here and there until your plants are well established and in about a year or two the garden should take care of itself. Whenever it rains you can be at rest with a cuppa tea, knowing that the water runoff from your property is clean. By incorporating a filtering strip or rain garden in your problem space, you become part of the solution for problem runoff that pollutes our waterways. At the same time these solutions offer an aesthetically beautiful area for humans and wildlife habitats.

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