8/3/2019 Arkansas; Rain Gardens Trend Taking Hold in Northwest Arkansas
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Through a new, attractive and environmentally sound land-scaping practice, Northwest Arkansas has joined the latest gar-dening trend. At least eight rain gardens have been installed inFayetteville alone. Rather than allowing rainwater runoff to flowover impervious surfaces and into storm sewers, these rain gardenscapture this natural resource and thus allow it to soak graduallyinto the ground and recharge the groundwater.
These shallow depressions or swales are planted with nativeperennial plants that can accept periods of heavy rain followed bylong periods of drought conditions. Rain gardens can absorb 30percent more water than a comparable parcel of turf. Such a gar-
den permits the water to filter slowly into the ground rather thanrun off into storm drains.
Over the past several years, Northwest Arkansas has experi-enced explosive population growth, accompanied by a correspon-ding increase in population density. This increase in populationand density in the region has created a loss of urban green space.Along with the loss of green space has come an increase in stormwater quantity and potential water quality problems.
Katie Teague, County Extension Agent with the Universityof Arkansas Cooperative Extension, specializes in water quality.Teague saw a need in Northwest Arkansas to implement rain gar-dens as a component of the storm water management system. Shebelieved that several highly visible demonstration gardens would
make residents more aware of the problems water runoff createsand would encourage citizens to participate actively in solutions tothose problems.
The concept of rain gardens has been around for about 15years, but until recently it was rarely implemented. Adapting theconcept to create an attractive flower garden is just now beginningto take hold among home gardeners.
Thanks to a grant from the U.S. Forest Service, a large groupof volunteers from various areas of the Fayetteville communitywere able to plan, install, maintain and promote eight highly visi-ble public demonstration sites. These gardens were placed strate-
gically near two elementary schools, two city parks, and a support-ive housing facility. Educational signage at each garden explainsthe benefits of rain gardens in Northwest Arkansas. As a result of this project, rain gardens are now being created at several homes,churches, schools and city facilities in the region. Teague attrib-utes the success of the demonstration rain gardens project inFayetteville to the collaboration of university, municipal, business,school and volunteer partners.
The first rain garden was placed next to Leverett Elementaryschool. Parents joined other volunteers on a blustery Saturday inApril to plant the garden. Students participated in planting theirown garden at Happy Hollow Elementary school. “We are excitedto be selected to host a rain garden for this new project in
The Gulley Park rain garden, shownhere, will catch runoff water from theroof of a nearby bathroom facility.
RAIN GARDENSA trend taking hold inNorthwest Arkansas
Story and photos by Joyce Mendenhall
8/3/2019 Arkansas; Rain Gardens Trend Taking Hold in Northwest Arkansas
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This rain garden detail,created by Jeff Huber,University of ArkansasCommunity DesignCenter, shows across-sectional viewof a typical raingarden design.
Fayetteville,” said Sharon Pepple, Principal of Happy Hollow.“Through a practical application, this garden will be an extensionof our science standards regarding ecosystems and naturalresources in our state.”
Two city parks, Gulley and Walker, were chosen for the next
demonstration sites. These gardens will be maintained by the Cityof Fayetteville’s Parks and Recreation Department. Four uniquegardens were planted on the site of the newly erected Seven HillsTransitional Living complex. Each of these gardens was designed
using all butterfly host and nectar plants.
GETTING OUT OF THE GUTTER AND INTO THE YARD
The lyrics of a popular children’s song read, “Rain, rain goaway.” But an increasingly important question is this: Where doesthe rain go when it goes away?
Rain is natural; stormwater isn’t. Government studies haveshown that up to 70 percent of the pollution in our streams, riversand lakes is carried there by stormwater. Most people never thinkabout stormwater, but at least half of the pollution carried bystormwater comes from things we do in our yards and gardens! Theaverage homeowner over-applies pesticides and fertilizers, often atrates many times that of farmers. Most of the rain that falls in
urban areas falls on impervious surfaces like roads and parking lots.As water runs along these impermeable surfaces, it picks up what-ever chemicals are there, from auto residuals like oil and exhaustto road treatments like tar and salts. The water runoff that reach-es lawns and gardens often picks up fertilizers, pesticides and weedkillers, which seep into the groundwater. This polluted runoff con-
tributes to habitat destruction, fish kills, stream siltration andreduction in drinking water quality.
Rain gardens help remove these pollutants from storm waterrunoff by allowing it to filter slowly into the ground rather thanrunning into a storm drain. Particular plants have the ability and
tolerance to take up high concentrations of toxic chemicals andeven process some of these chemicals into less toxic derivatives.
A “GROWING” SOLUTION TO WATER POLLUTION
There are many benefits to rain gardens besides their obviouscapacity to absorb stormwater and reduce runoff. For one thing,the native plants planted in them attract all kinds of wildlife,including birds and butterflies. These are attractive additions tothe landscape, enhancing the beauty of the neighborhood
Native perennial flowers, grasses, and shrubs that prefer ortolerate moist soils thrive in rain gardens. These local plants tend
to be well-adapted to a range of regional conditions and will flour-ish without chemical fertilizers and pesticides.
Prairie flowers have deep roots that often go down ten feet.When the weather is dry, they can access sources of water unavail-able to other vegetation and when it is wet, their root structuresprovide deep conduits into which rain can flow.
ENHANCING YOUR HOME LANDSCAPE
AND PROTECTING WATER QUALITY
You might want to develop your own personal rain garden.
Determine what kind of soils you have on your property. Estimate
the area from which your garden will get rain. Then take 20, 30,and 60 percent of that for sand, silty, and clay soils, respectively.The result is how big your garden should be. Single family homeswill typically range from 150 to 400 square feet in breadth sinceeach roof usually has multiple rain spouts or runoff areas.
The normal depth for a rain garden is from three to six inch-es. Adjust the depth to the infiltration rate. Poor infiltration callsfor a shallow depression. If your soils suck up water, make your gar-den deeper to increase its storage capacity. Organic matter andsand will help improve the infiltration rate and water-holdingcapacity of soil with a high clay content.
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It is important to realize that a rain garden is not a water gardenor pond. Whereas a pond holds water all the time and can supportaquatic plant and animal species, a rain garden is more like a sponge.Although water pools as runoff collects, the soil in a rain garden willabsorb it within two to four days, an important characteristic thatprevents its becoming a mosquito-breeding site. Because of its excel-lent drainage, the soil in a rain garden may actually become quite dry.
Siting is important. Never place a rain garden against the houseor on top of a septic tank drain field. Keep a ten-foot distance fromthe foundation. Twenty feet is better. One common-sense rule is toplace your rain garden in line with the basic drainage pattern of your
yard, so overflow will drain away from the house.The choice of plants is up to the gardener. Just be sure to con-
sider the ability of each plant to flourish in both extreme wet and dryconditions. A suggested list of rain garden plants for
Northwest Arkansas can be found at the University of ArkansasCooperative Extension Service’s website: http://ppc.uaex.edu/ NWA_native_plants.pdf .
Be sure to mulch the garden immediately after planting. Mulchacts as a sponge to capture heavy metals, oils, and grease. As themulch decays, bacteria and plant roots have a chance to break downthe pollutants. Mulch also retains moisture and thus benefits the gar-den during a drought. Shredded hardwood works particularly well inrain gardens because it doesn’t float or blow away.
Planting a rain garden may seem like a small thing, but if you cal-culate the amount of rain that runs off your roof, you probably will besurprised. Did you know that one inch of rain over one acre equalsmore than 27,000 gallons of water?
Keeping rain where it falls by directing it into an attractive raingarden is a natural solution. You not only get a garden out of it, but
you also protect our rivers, streams and lakes from pollution and mit-igate the effects of drought. Thereby any gardener can become part ofa beautiful solution to water runoff!
Joyce Mendenhall is a Master Gardener who gardens in Fayetteville. She
designed the four Seven Hills Supportive Housing facility’s rain gardens,
which feature plants that serve as butterfly host plants and nectar sources.
PLANTS USED IN FAYETTEVILLE
RAIN GARDENS
Perennials and Herbaceous Plants
Amsonia, Amsonia sp.
Aster, New England, Aster novae-anglia
Beardtongue, Penstemon digitalis ‘Huskers Red’
Black-eyed Susan, Rudbeckia fulgida ‘Goldstrum’
Blazing Star, Liatris spicata ‘Kobod’
Blue Star, Amsonia hubrictii Cardinal Flower, Lobelia speciosa
Catmint, Nepeta cataria ‘Walker’s Low’
Fern,Sensitive, Onoclea sensibilis
Hypericum, Hypericum profificum
Hyssop, Agastache rupestris
Iris,Blue Flag, Iris versicolor
Joe-Pye Weed, Eupatorium Purpureum
Milkweed, Asclepias
Obedient Plant, Physostegia virginiana
Ornamental Grass, Miscanthus sinensis ‘Adagio’ and ‘Little Kittens’
Ponytail Grass, Stipa tenuissima
Rush, Striped, Baumea rebiginos ‘Variegata’
Russian Sage, Perovskia atriplicifolia
Tickseed, Golden, Coreopsis tinctoria
Shrubs
Butterfly Bush, Buddleia davidii
Dogwood, Red Twig, Cornus sericea
Inkberry, Ilex glabra
Spicebush, Northern, Lindera benzoin
Spirea, Bluebeard, Caryopteris x Clandonensi
Trees
Ash,Green, Fraxinus pennsylvanica
Ash,White, Fraxinus americana
Blackgum, Nyssa sylvatica
Elm, Ulmus glabra ‘Camperdownii ’
Magnolia, Sweet Bay, Magnolia virginiana
Maple,Red, Acer rubrum
Redbud, Cercis canadensis
Serviceberry, Amelanchier arborea
Sweetgum, American, Liquidambar styraciflua
Witch Hazel, Hammamelis virginiana
Yaupon Holly, Dwarf, Ilex vomitoria ‘Nana’
m
The Walker Park rain garden,shown here, captures stormwaterrunoff from a park pavilion roof.
Blazing star, Liatris spicata , shown here, isa native prairie plantwith deep roots whichact as conduits intowhich rain can flow.
Great blue lobelia, Lobelia siphilitica , shown here,provides outstanding colorin the rain garden.
Black-eyed Susan,Rudbeckia fulgida,shown here, is anothergreat native plant foruse in the rain garden.
Volunteers, shown here, put thefinishing touches on a rain garden
at Happy Hollow Elementary School.
