Oct. 15, 2019
What’s Up? Annapolis
Our lovely, lush, green lawns contribute significantly to the Chesapeake Bay pollution. The Chesapeake Bay Foundation (CBF) continues to raise the alarm on the dire condition of the Bay. In a recent report, CBF noted, “Computer modeling by the Chesapeake Bay Program suggests 9 million more pounds of nitrogen will wash into the bay due to climate change and 500,000 pounds of phosphorous.” Much of that excess nitrogen and phosphorous comes as run-off from residential lawns.
We have good intentions. Most of us try to protect the earth, the oceans, the Chesapeake Bay, the streams that intersect our town and cities, and our own neighborhoods. Those of us who putter in the garden try to use less fertilizer, less weed killer, less watering, more mulching, more composting, more cultivation of indigenous plants—we keep looking for ways, small or large, to turn around those disheartening statistics on the pollution of the Chesapeake Bay watershed.
Perhaps instead of lamenting our guilt, we can tackle one significant source of pollution: our lush lawns. I can offer three interesting alternatives to grassy knolls and putting-green sod. Why not replace that green carpet with a (1) pond or a (2) rock garden? What about a pretty and practical (3) rain garden?
Wait! Why choose between the three? Why not replace your side yard with a rock garden, find a shady spot in the front lawn for a soothing pond, and collect runoff with a rain garden just along the driveway’s edge? Those changes could reduce the onerous grass cutting and leaf raking chores significantly, and help the Bay as well. Imagine if each of us could diminish the amount of grass we grow by 25 or 50 percent; what a difference that would make in reducing excess nitrogen and phosphorous flowing into our water supply, as well as reducing the use of treated or aquifer water.
Just a little preliminary warning here: Unless you’re a weight lifter or a tri-athlete, I don’t recommend you try constructing these specialty gardens yourself. You can make the plan, perhaps even draw up a few design diagrams. Then, consult with your landscaper, landscape architect, or gardener to proceed with the actual scraping and digging, lining, and mounding.
Let’s begin with the pond. If you have a grassy area that is relatively free of tree roots and large shrubs, that may be the spot for a pond. You’ll want to consider the size and depth of the pond you envision. To help with that visualization, use lightweight rope, cord, or even your garden hose to roughly layout the design and size of your pond on the location you’ve chosen. As you arrange the rope or hose, think about where the sun will hit your pond and for how long. (You may decide to stock your pond with goldfish or koi, and if you do, the fish will need some sunlight but not such intense sunlight, that your pond becomes a boiling pot for the little swimmers.) Also, will tall trees overhang your pond’s location? Picking branches and leaves out of the pond could become annoying.
Now the fun begins: planting in and around your pond. Placing plants in the pond will depend on the size and depth of your pond. There are five types of plants to consider:
Deep water plants, such as water lilies, are put in pots of clay soil topped by gravel or pebbles, then settled on the bottom of the pond. (Be sure that most of the plant’s stalk and foliage are above water.)
Submerged plants, such as lotus, are entirely underwater, and only the leaves and blooms break the surface.
Floating plants, such as water hyacinth or water lettuce, need no soil. (Caution: these pretty, tiny guys look innocent, but before you know it they can choke out everything else in the pond. You’ll have to keep a close eye and thin the plants without mercy.)
Marginal plants, such as irises, can live with their bulbs and roots submerged or planted in the soil near your pond. (They’ll soften the edges of the pond so it appears the pond is a natural part of the landscape.)
Bog plants, such as cattails and spider plants, thrive in the mud. (Perfect if you have a spillway or drain from the pond where the soil remains pretty soggy.)
Among the pretty plants that flourish in a rock garden are:
Rock cress (Arabis): They have pink or white spring blossoms and resist heat and drought. (Pinch the dead blooms to encourage the foliage.)
Sedum: These hardy dears come in a variety of colors and forms. Who can resist the hens and chicks? You can by “sedum tiles;” they’re pre-planted squares that you can simply lay over an area. (Maybe to camouflage that spot where you ran out of rocks that were just the right size.)
Candy tuft: These bloom white in the spring. They’re a bit taller, maybe four inches, and are unpopular with the deer—so you won’t be providing deer-buffets.
Red creeping thyme: These give you a showy addition to the rock garden. It’s tough and, when crushed, the leaves have a lovely fragrance.
Decorative grasses are also an option. I hesitate recommending these, however. The problem I’ve seen with the clumps of graceful grasses is that as they age, the center of the clump dies, and only the outer ring produces the grass fronds. If you don’t divide and trim every clump, every year, you’ll soon find it’s impossible to do so without a chainsaw and a couple of jack hammers! So, be warned.
Now, maybe you’re thinking, “If I’m trying to use natural plantings, less water, and less fertilizer, why would I want a pond? Won’t that use more water?” Surprisingly, a pond uses little water. Once it’s filled and you’ve installed a small bubbler to keep the water aerated, the pond will take care of itself. The movement and aeration created by the small bubbler will prevent the laying of mosquito larvae. Of course, you may want to install a fountain—fairly easy to accomplish—or a waterfall, a far more complex and demanding project. If your aeration system is working, you’ll only need to top-off the pond’s water level every three to four weeks. If possible, use unchlorinated water; plants, frogs, and fish will be happier and healthier.
As much fun as it will be choosing entirely different qualities of the plants in and around your pond, consider that you may want to leave some open water, even if that’s only a two-foot circle in the middle of the pond. The reflections in the water, the sparkles of sunbeams on the surface, the sight of dragonflies hovering—those are as lovely as the plants you’ve chosen.
Finally, try to leave at least one overhang, a flagstone or a sturdy branch that juts out over the water. You will find it lures the little songbirds to come and drink. If you’re lucky, turtles and frogs may discover your pond, too. They’ll all enjoy your little makeshift diving board.
Now, what about the rock garden? This overlooked gem can provide the perfect solution for that too-sunny spot where the plants frequently fry, or mask that section of your property where the builder left so much rubble that no amount of mulch can coax shrubs or flowers to flourish.
Here, too, use that piece of hose or rope and lay out a shape that looks natural and the right size.
You might even have a rock garden about your pond, if the incline of the land allows. Here’s where you’ll need some strong backs and arms—maybe those teenagers keeping in shape for lacrosse or soccer could lift rocks instead of weights. Lay the rocks in concentric circles. Fill the middle of the circle with sandy soil or peat with lava rock mixed in for each tier. Avoid laying the rocks in too regular a pattern. Mix sizes and colors as you build up your rock garden.
The soil that you’re using to “fill in” the center of each tier will feed the roots of the plants you’ll be adding. A major advantage of a rock garden is that it will be worry-free, if you choose your plants carefully. (You’ll occasionally have to weed out volunteer crabgrass and other invaders, but those unwanted visitors will be easy to spot among the low, lush vegetation.)
Tuck your tiny plants between the rocks, using a thin stick or finger to push the roots down into the crevice; then add a bit of soil on top.
Last of all, take some of those leftover rocks, and some of the marginal and bog plants you used at the pond, and finish off your eco-friendly yard with that rain garden. (This will be easy compared with the pond and the rock garden.) The purpose of a rain garden is to take up the excess water that runs off your driveway, sidewalks, patio—any impermeable surface—and encourage that polluted water to soak down into the soil where it will be cleansed and then returned to the aquifer. This process is completely passive, so you want to think about where rain water and sprinkler hose water runs naturally in your yard.
You’ll probably be able to identify the area by its spongy and maybe a bit stinky character. Now you’ll transform that area into a lovely, useful rain garden. Following the natural indentation of the land, dig out the boggy area. Create just a gentle dent in the surface; don’t get carried away with a deep trench. If you know that quantities of water will likely stand for a bit in your rain garden, layer part of the shallow ditch with “river rocks.” (That’s a designation for large, usually oval, and smooth rocks.) Then, plant your bog and marginal plants along the sides and bottom of your indentation. You might add some creeping phlox and moss to the sides, too, for added color and a softening, natural effect.
Before long, the plants will take hold, the rains will come and go, and your rain garden will transform from a gash into a soft dent—quite natural to its location. Below the surface, clean water will fill the aquifers, and healing the earth will continue.
The crabs and herons, as well as your neighbors and fellow citizens, will benefit from your labors to improve our eco-system.
These gardens are dream gardens. I’d love to have one of each. The rain garden looks most possible in my area but I love looking at each of them in this article. A source of meditation as if they were real.
I didn’t know grass was a blight to our ecology before. An informative article and–as I said–pretty to look at!
Thank you, Grace.
Very interesting!! Loved it.