Rain gardens retain water

March 28, 2009|By JEFF RUGG / Creators Syndicate

Q: I have been thinking about putting in a rain garden. Do you have any advice?

A: A rain garden is similar to other perennial flowerbeds that you might build - it just holds water longer. Rather than building a raised flowerbed by adding organic matter to get better drainage, a rain garden is a flowerbed built slightly lower so that water accumulates.

Rain gardens provide several benefits to your landscape. They trap water that will slowly soak into the soil and not run off. This water helps your landscape because more water is available for a longer time deeper underground. The water your plants don't use will eventually reach the groundwater that in many communities supplies the wells that are slowly going dry.

Any water that doesn't immediately wash into the storm drains reduces the amount of local flooding and shoreline erosion in retention ponds and rivers. In the long run, the water that has soaked into the ground also helps to keep an adequate flow of water in streams during drought.


A rain garden is planted with low maintenance perennial flowering plants. These hardy plants require less care and fertilizer than a lawn. As the plants bloom, they attract birds and butterflies. Most rain garden plants grow best in full sun, but a half-day of sun will work, too. Choose rain garden plants that will be the right height for your landscape. There are a variety of blooming times, color choices and flower fragrances.

Every part of the country has shoreline, swamp or wet prairie plants that will grow in a rain garden. Some like wetter soil, so plant them in the deeper center area. Like any perennial flowerbed, the plants will need to be watered if it doesn't rain after they are planted. Once they get established they won't need to be watered.

The construction is easy. Measure the area that the water will be coming from. If the water is coming from the roof gutters, then measure how many square feet of roof area there is. If the rain garden is taking the water from a large sloped grassy area, measure the square footage of the lawn. The rain garden should be about one-third as big as the area that supplies the water.

Pick a low, flat area in full sun at least 10 feet from the house that is not over a septic system. Dig a level-bottomed hole from two to six inches deep with sides that slope down to the flat bottom. A deeper water garden will hold more water longer.

Channel the water to the rain garden with the downspout, a PVC pipe or a shallow trench. Because of the lay of the land, it may be necessary to build rain gardens in both the front and backyards. In heavy rains, the rain garden may need to overflow, so make sure the water drains away from the house.

Mosquitoes should not be a problem because the rain garden is not supposed to have visible water left standing in it for more than a few hours. Even if it rains every day or two, there should not be standing water long enough for mosquitoes to become adults. The eggs need to float in water for a week to hatch, so they will have dried out and died before then.

Q: I have been trying to decide if I want to plant a peach tree or a pear tree. I think I really only have room for one tree. I have read that I need to get two pear trees if I want to get fruit. Is there any way around this situation if I decide I want the pears?

A: Most fruit tree types are self-pollinating, but some are not. To get fruit from apples, pears, sweet cherries and plums you need more than one tree from a different variety. A few of the self-pollinating types of trees will produce more fruit that is larger in size if they are pollinated from a different variety.

The most common pear is the Bartlett, which is self-pollinating. It has better production if there is a cross-pollinating tree nearby. Another one is the Stark Honeysweet. There are also potential incompatibility problems, as some fruit trees don't cross-pollinate each other, even when both varieties need other varieties to be pollinated. The Bartlett pear won't cross-pollinate with the Seckel pear variety.

European pears and Asian pears can cross-pollinate except that Asian pears tend to bloom later than the Europeans. A few of the Europeans do bloom late enough to pollinate some Asian pears.

Peaches are self-pollinators, so they don't need the extra tree. You might consider a second peach tree to get a long season of fruit ripening. Some peaches produce fruit several weeks earlier than others, so you can have a longer season of eating fresh peaches.

o E-mail questions to Jeff Rugg, Kendall County unit educator, University of Illinois Extension at

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