Recently, on one of those steamy, hazy days we’ve had so many of this summer, I visited Water Resource Specialist Mary Gilbertson and “her” gardens at the Portland Water District’s Ecology Center on Route 35 in Standish.

I’d gotten to know Mary a bit from doing a story on PWD’s matching grants program, designed to alleviate problems of erosion and runoff on Sebago Lake watershed properties.

But on this, my first visit to the Ecology Center, I came for a tour of the gardens.

The Center has a great hillside garden in back, demonstrating the use of native shrubs and groundcovers to hold a slope. They even have suggestions for mulch that will not wash off of the hillside. And the selections used certainly prove that native doesn’t have to mean boring.

It inspired me to get busy and rework some of the sloping areas in my own yard – spots that are currently a nuisance to mow. After all, what good is a grass carpet if it’s too steep an area to walk on?

At the Center, I also saw a well-matured sunny garden, filled with different varieties of daylilies, as well as purple coneflower, Russian sage, and many more tough yet attractive perennials.

But I came particularly to see the new rain garden the Center installed this spring.

For those of you that have begun perennial gardens, as opposed to inheriting them already matured, you know that it takes a year – or two, or three – for the plants to fill in. In other words, as attractive as this new garden is this year, next year and beyond it will only increase in beauty.

And it’s so practical, too. The premise behind the plot is simple: Rather than allowing all the water that pours off the roof during a rainstorm to run, unfiltered, into the watershed, direct that runoff into an area designed to absorb large quantities of water quickly.

This is accomplished beautifully with a properly designed rain garden.

The ideal rain garden is located ten or more feet away from the building with an area about 20-30 percent of the drainage area.

The center of the bed should be at least six inches below the grade of the land surrounding it so that the water is funneled to that spot. The soil itself is comprised of 50-60 percent sand, 20-30 percent topsoil, and 20-30 percent compost. You can use some of the soil from that area as long as it’s not clay.

At the Ecology Center, they have created a swale to channel water from the gutter’s downspout into the garden more effectively. They lined the swale with landscape fabric and covered the fabric with rock. This feature nearly guarantees that the water will go to the garden.

The rules for planting a rain garden are simple and logical. If located in a sunny area, choose sun-loving plant. For shade – you guessed it. And many of the plants are most likely ones you’re already familiar with. The key is, in a rain garden, the lowest point in the garden – usually the middle – requires water-loving plants, the area surrounding the middle needs plants with high moisture requirements, and those areas farthest from the center need plants that can stand up to dry conditions.

Mary, who lives with her husband in Saco and frequently bikes the 20 miles to or from work, loves to garden at home, as well. While growing up in Washington State, she helped her mother, an avid gardener, with weeding and other garden chores.

Mary’s favorite garden advice comes from her mother: “When you buy perennials, buy small because they’re cheaper, but for trees and shrubs, buy the biggest you can afford because they take so long to grow.”

A visit to the Ecology Center is worth your trip. Not only can you learn from their gardens, but they also have a lending library of gardening books and books on other ecological issues. The book room includes resources for teachers, free informational and how-to pamphlets, and an attractive reading corner geared to children.