Easy Gardener • Pat Howell
	Onto the front burner November, 2005

The last three or four months have been amazing, weather-wise. We’ve had prolonged heat and record drought (60-plus days with less than one inch of rain!), hurricanes, and tornadoes. Who knows what is around the corner?

As any gardener will tell you, Mother Nature knows how to keep us humble.

Landscaping topics that have been lurking in the background for a while are now starting to reach the front burner; for example, rain gardens. The topic is timely because we are finally getting enough rain to put back some of what we lost over this summer; and most welcome it is.

Of course, one has to be careful what one asks for, because one might get it. Some of you may have found that abundant rain that comes down all at one time is a problem, not a boon. Keeping the water out of your basement, keeping your soil from washing away, keeping your feet dry when you step out of your car, keeping pollutants out of the local creeks: the solutions to these problems/irritants are grouped under Stormwater Management.

When the water races across your property and into the gutters and streets and then into the storm-drains, it picks up all kinds of chemical pollution from the paved areas. This toxic water is then deposited directly into the streams and, ultimately, the Chesapeake Bay.

So, if you worry about the water quality on the bay, you will want to explore some ideas to keep your clean water pollutant-free. Furthermore, if you are goal-oriented, and you want to keep that excess water out of your basement, not to mention the creeks, a sponge garden/rain garden is possibly the best answer.

A rain garden and a sponge garden are interchangeable terms. Put simply, if you remove your lawn (which does a very poor job of absorbing excess rainwater, and then plant trees, shrubs and perennials, you can create a ‘sponge’ to hold and filter that excess water so it slowly soaks into the soil, where layers of sand and rocks below ground filter out pollutants naturally; and then the clean water flows to the streams.

According to Ed Murtagh, a volunteer with Friends of Sligo Creek, “gardening may be one of the best defenses in the fight against poor water quality.”
The September-October 2005 issue of the locally published Washington Gardener (see list of resources below) has a very helpful article by Allison Gillespie, “Sponge Gardening: Soaking Up the Rain.” Gillespie also quotes Ed Murtagh: “Rain gardens are specially designed depressions which are filled with plants and designed to collect and store rainwater. Underneath these gardens, layers of sand, rocks and soil can act as natural filters.

“The location of a rain garden is usually the key to its success. A well-designed rain garden will only allow water to stand for a very short amount of time before releasing it, unlike garden ponds which are designed to hold water indefinitely.

“Trees and certain perennials, it seems, can act like drinking straws set inside those garden sponges. The root systems of these can also help to break up the soil and improve rain water filtration.

“In contrast, grass-filled lawns absorb very little water. They also often require more maintenance and are treated with large amounts of chemicals, many of which end up as pollutants in run-off when rain washes over the grass blades during large storms.” (We know you would never have such a lawn, but there’s always the other guy!)

As an excellent example of where a rain garden could serve our city, Takoma Park has a public garden named Forest Park, at the intersection of Prince George Avenue and Elm Avenue. Serious erosion is visible at the lowest point (on the Elm Avenue side). But the excess water begins at the higher parts of the garden, particularly on the lawn and the paved play areas, which serve as sluiceways. (Go out there in a rain and you will see instantly what we mean.)

To capture the excessive runoff, and to filter and utilize this water rather than sending it into the storm sewer, a rain garden at the low point could serve as a sponge. Furthermore, attractive native plants can be added to the site, and voila—a Demonstration Project.

This idea is being explored as we speak. To learn more, contact Ed Murtagh, or Ann Hoffnar at Friends of Sligo Creek (See Resources). And please stay tuned here. This is fun and important stuff! We will be revisiting this subject in future columns.

Resources:
• Washington Gardener magazine: Kathy Jentz, Editor/Publisher:
editor@washingtongardener.com or 301-588-6894.
• Allison Gillespie gardens locally, and can be contacted at alg@nasw.org.
• Ed Murtagh: edward_b_murtagh@yahoo.com
• Friends of Sligo Creek: www.fosc.org or Ann Hoffnar:
ann.hoffnar@starpower.net or 301-585-8891.

Pat Howell is a Takoma Park gardener and landscape designer/contractor. She is available for hand-holding and answering questions through Deephaven Landscapers.