Rain gardens are a landscaping trend of their own in 2017. If you are looking for a way to reduce your water bill, reduce yard work so that you can actually enjoy your yard, and add low maintenance curb or landscaping appeal to your home, as most homeowners are, a rain garden meets all three goals with a single addition to your landscape.
The Why Behind The Rain Garden Trend
Rain gardens are a natural extension of the ever-growing interest in reducing carbon footprints, sustainability, and eco-friendly living and working environments. Some years ago, some states and cities began experimenting with planting rain gardens to remove pollutants from the runoff from highways, streets, and parking lots before the water was allowed to enter storm sewers and flow, untreated, into local rivers and streams. According to the Michigan State University Extension Service, studies show that 70 percent of the pollution in rivers, lakes, and streams comes from lawns and gardens.
A rain garden that receives the runoff from your lawn, sidewalks, driveway, or roof by way of your gutters and downspouts removes pollutants from that water before allowing it to enter the storm sewers along your street. Because the runoff from your roof waters the rain garden, you reduce the time and money you spend on watering that area of your lawn. Since you won’t be mowing the section of your yard dedicated to your rain garden, you are reducing the time you spend on yard work. In addition, by using less water, reducing water pollution, and using less of the electricity or gasoline that powers your lawn mower, you are living in a more sustainable way.
Another benefit that you may never have realized is that planting a rain garden in your yard helps reduce local flooding, such as the kind that may occur in the street in front of your house during an extremely heavy rainfall. Three Rivers Rain Garden Alliance, located in western Pennsylvania, reveals that the storm and sewage systems are still linked in many areas and just a tenth of an inch of rainfall can cause them to overflow. Again according to Three Rivers Rain Garden Alliance, a single rain garden can absorb a few inches of runoff during a rainstorm. If every home in the neighborhood had a rain garden, it might completely eliminate street flooding.
A less visible reason for creating a rain garden is underground. After your rain garden clears any pollutants from the runoff from your roof, lawn, and driveway, it passes through as clean water to add to the supply of ground water beneath your community.
In addition to improving the eco-system in your community by producing clean groundwater, your rain garden provides food, water, and natural habitat for bees, butterflies, and birds. Because rain gardens help drain standing water, they aren’t so friendly to mosquitoes. Rain gardens help reduce the mosquito population by eliminating puddles where they might breed.
Deciding on a Site and Size for Your Rain Garden
The first thing to keep in mind is that your rain garden should be at least 10’ from your house to prevent water damage to your foundation or basement walls. You should also put it at some distance away from your driveway, sidewalks, and patio to prevent erosion. The next thing to find out is how the water flows across your yard. Take an umbrella and go out into the rain to observe conditions for yourself. Which direction does the water run? Where does it create puddles or muddy, marshy areas? Since water already flows to that area, that would be a natural place for a water garden, especially if there is a natural depression in the ground. The sides of that depression do need to have the right degree of slope to make sure that your rain garden receives a sufficient amount of water. Your landscaping contractor will have the equipment to create the proper slope.
Have your local extension service test the soil in the areas of your yard where the water naturally settles to see which is most suited to a rain garden. You don’t want the water to stand around in the area, but you also don’t want it to drain off so quickly that it isn’t filtered. You can test how quickly the water drains by digging a shallow hole and pouring water into it. If the water hasn’t drained off after a couple of days, then that soil contains too much clay.
If you can’t find a spot with the right type of soil, you can mix 30 to 40 percent of a sandy or loamy top soil with 30 to 40 percent compost and 30 percent sand and till that into the area where you plan to create your water garden, or after your landscaping contractor digs out the area to create the proper size and slope, you can have it filled with pre-mixed rain garden soil.
Your rain garden should include an area of between 100 and 300 square feet and be 4” to 8” deep. The size of your garden depends on how much rain your area receives, and the depth depends on the amount of slope your landscaping contractor creates. The more rainfall you receive in your area; the larger your garden should be to handle it. The greater the slope guiding run off into your rain garden; the deeper your garden will need to be to handle the water it will receive. Your landscaping contractor will know the best combination of size, slope, and depth for your area and your yard.
Picking the Plants For Your Rain Garden
In general, when deciding on plants for your rain garden, you should choose mature plants with long roots. Seeds or seedlings with shallow, undeveloped root systems will simply wash away. Although shrubs prefer well-drained soils, you will need to include them to prevent soil erosion. If you live in an area that receives a lot of rain, add several shrubs to your garden. Naturally, you will want wetland plants. The U. S. Army Corps of Engineers offers the National Wetland Plant List on their website.
Trends for Rain Gardens
While rain gardens are a trend in themselves, the plants recommended for them also represent landscaping trends. Homeowners are seeking out local varieties of plants because these are best adapted to local weather conditions such as variations in temperatures and rainfall. Local wetland plants will be the ones that thrive the best in your rain garden as well. Local sourcing is a trend you should definitely follow when picking rain garden plants. You can download a list of wetland plants specifically for Franklin, TN from the Army Corps of Engineers website. It includes wetland trees, shrubs, and plants with their common and scientific name, but unfortunately, it does not include pictures. In particular, look for “marginal” plants. These are the plants that thrive on the outer boundaries of a wetland area. They have adapted to survive when the soil is moist as well as when it dries out during a period without rain, and your rain garden is likely to experience both conditions.
Textures are a trend indoors and out. The shrubs you choose provide a contrast with your plants, but find pictures of the wetland plants for your state, and look for interesting contrasts. Plant locally native rushes, sedges, and grasses over about one-third to one-half of your rain garden, not only for the contrast they provide but also because their deep root systems will work with the shrubs to prevent erosion.
In addition, your rain garden should include a ponding zone where pollutants and leaves, twigs, grass clippings, and other organic materials can settle and collect. The use of locally sourced rocks is a hardscaping trend, and placing a few rocks around the pond or elsewhere in your rain garden creates a natural look while providing another contrasting texture. If you create a swale to guide water from your downspouts to your rain garden, place rocks along its length for a natural, stream-like look.
To create the most natural look, your plants should be grouped in large tufts or drifts. This allows you to introduce another hardscaping trend to your rain garden – color blocking. Block tufts of foliage with blooming plants or create blocks based on light and dark or contrasting colors.
Also remember another trend, the most popular choices for flower colors are bright, bold colors. So, choose a look that coordinates with the rest of your landscaping, but if you have gone with neutrals elsewhere, don’t be timid. Use your rain garden to add a spot of vivid color to your yard.
As with any newly planted area, your rain garden will need a period of watering, mulching, and weeding as the plants become established. Once that initial period has passed though, your rain garden may be the least demanding, easiest to care for area of your yard, and you can feel good about all of the work it does to improve the environment for your neighborhood and your community, even if everyone else thinks that it just grows there looking very pretty.
If you would like more installation and design information about rain gardens, you can contact us here, or even better, give us a call at (615) 581-2045. We look forward to hearing from you!