Rain Gardens: trend taking hold in Northwest Arkansas

1. The Gulley Park rain garden, shown
here, will catch runoff water from the
roof of a nearby bathroom facility.
RAIN GARDENS Story and photos by Joyce Mendenhall
A trend taking hold in
Northwest Arkansas
Through a new, attractive and environmentally sound land- make residents more aware of the problems water runoff creates
scaping practice, Northwest Arkansas has joined the latest gar- and would encourage citizens to participate actively in solutions to
dening trend. At least eight rain gardens have been installed in those problems.
Fayetteville alone. Rather than allowing rainwater runoff to flow The concept of rain gardens has been around for about 15
over impervious surfaces and into storm sewers, these rain gardens years, but until recently it was rarely implemented. Adapting the
capture this natural resource and thus allow it to soak gradually concept to create an attractive flower garden is just now beginning
into the ground and recharge the groundwater. to take hold among home gardeners.
These shallow depressions or swales are planted with native Thanks to a grant from the U.S. Forest Service, a large group
perennial plants that can accept periods of heavy rain followed by of volunteers from various areas of the Fayetteville community
long periods of drought conditions. Rain gardens can absorb 30 were able to plan, install, maintain and promote eight highly visi-
percent more water than a comparable parcel of turf. Such a gar- ble public demonstration sites. These gardens were placed strate-
den permits the water to filter slowly into the ground rather than gically near two elementary schools, two city parks, and a support-
run off into storm drains. ive housing facility. Educational signage at each garden explains
Over the past several years, Northwest Arkansas has experi- the benefits of rain gardens in Northwest Arkansas. As a result of
enced explosive population growth, accompanied by a correspon- this project, rain gardens are now being created at several homes,
ding increase in population density. This increase in population churches, schools and city facilities in the region. Teague attrib-
and density in the region has created a loss of urban green space. utes the success of the demonstration rain gardens project in
Along with the loss of green space has come an increase in storm Fayetteville to the collaboration of university, municipal, business,
Arkansas Gardener
water quantity and potential water quality problems. school and volunteer partners.
Katie Teague, County Extension Agent with the University The first rain garden was placed next to Leverett Elementary
of Arkansas Cooperative Extension, specializes in water quality. school. Parents joined other volunteers on a blustery Saturday in
Teague saw a need in Northwest Arkansas to implement rain gar- April to plant the garden. Students participated in planting their
dens as a component of the storm water management system. She own garden at Happy Hollow Elementary school. “We are excited
believed that several highly visible demonstration gardens would to be selected to host a rain garden for this new project in
42 w w w. a r k a n s a s g a r d e n e r. c o m

2. Fayetteville,” said Sharon Pepple, Principal of Happy Hollow. tolerance to take up high concentrations of toxic chemicals and
“Through a practical application, this garden will be an extension even process some of these chemicals into less toxic derivatives.
of our science standards regarding ecosystems and natural
resources in our state.” A “GROWING” SOLUTION TO WATER POLLUTION
Two city parks, Gulley and Walker, were chosen for the next There are many benefits to rain gardens besides their obvious
demonstration sites. These gardens will be maintained by the City capacity to absorb stormwater and reduce runoff. For one thing,
of Fayetteville’s Parks and Recreation Department. Four unique the native plants planted in them attract all kinds of wildlife,
gardens were planted on the site of the newly erected Seven Hills including birds and butterflies. These are attractive additions to
Transitional Living complex. Each of these gardens was designed the landscape, enhancing the beauty of the neighborhood
using all butterfly host and nectar plants. Native perennial flowers, grasses, and shrubs that prefer or
tolerate moist soils thrive in rain gardens. These local plants tend
GETTING OUT OF THE GUTTER AND INTO THE YARD to be well-adapted to a range of regional conditions and will flour-
The lyrics of a popular children’s song read, “Rain, rain go ish without chemical fertilizers and pesticides.
away.” But an increasingly important question is this: Where does Prairie flowers have deep roots that often go down ten feet.
the rain go when it goes away? When the weather is dry, they can access sources of water unavail-
Rain is natural; stormwater isn’t. Government studies have able to other vegetation and when it is wet, their root structures
shown that up to 70 percent of the pollution in our streams, rivers provide deep conduits into which rain can flow.
and lakes is carried there by stormwater. Most people never think
about stormwater, but at least half of the pollution carried by ENHANCING YOUR HOME LANDSCAPE
stormwater comes from things we do in our yards and gardens! The AND PROTECTING WATER QUALITY
average homeowner over-applies pesticides and fertilizers, often at You might want to develop your own personal rain garden.
rates many times that of farmers. Most of the rain that falls in Determine what kind of soils you have on your property. Estimate
urban areas falls on impervious surfaces like roads and parking lots. the area from which your garden will get rain. Then take 20, 30,
As water runs along these impermeable surfaces, it picks up what- and 60 percent of that for sand, silty, and clay soils, respectively.
ever chemicals are there, from auto residuals like oil and exhaust The result is how big your garden should be. Single family homes
to road treatments like tar and salts. The water runoff that reach- will typically range from 150 to 400 square feet in breadth since
es lawns and gardens often picks up fertilizers, pesticides and weed each roof usually has multiple rain spouts or runoff areas.
killers, which seep into the groundwater. This polluted runoff con- The normal depth for a rain garden is from three to six inch-
tributes to habitat destruction, fish kills, stream siltration and es. Adjust the depth to the infiltration rate. Poor infiltration calls
reduction in drinking water quality. for a shallow depression. If your soils suck up water, make your gar-
Rain gardens help remove these pollutants from storm water den deeper to increase its storage capacity. Organic matter and
runoff by allowing it to filter slowly into the ground rather than sand will help improve the infiltration rate and water-holding
running into a storm drain. Particular plants have the ability and capacity of soil with a high clay content.
This rain garden detail,
created by Jeff Huber,
University of Arkansas
Community Design
Center, shows a
cross-sectional view
of a typical rain
garden design.
February 2008
w w w. a r k a n s a s g a r d e n e r. c o m 43

3. PLANTS USED IN FAYETTEVILLE
RAIN GARDENS
Perennials and Herbaceous Plants
Amsonia, Amsonia sp.
Aster, New England, Aster novae-anglia
Beardtongue, Penstemon digitalis ‘Huskers Red’
The Walker Park rain garden,
Black-eyed Susan, Rudbeckia fulgida ‘Goldstrum’ shown here, captures stormwater
Blazing Star, Liatris spicata ‘Kobod’ runoff from a park pavilion roof.
Blue Star, Amsonia hubrictii
Cardinal Flower, Lobelia speciosa
Catmint, Nepeta cataria ‘Walker’s Low’
Fern,Sensitive, Onoclea sensibilis
Hypericum, Hypericum profificum
Hyssop, Agastache rupestris Black-eyed Susan,
Iris,Blue Flag, Iris versicolor Rudbeckia fulgida,
Joe-Pye Weed, Eupatorium Purpureum shown here, is another
great native plant for
Milkweed, Asclepias use in the rain garden.
Obedient Plant, Physostegia virginiana
Ornamental Grass, Miscanthus sinensis ‘Adagio’ and ‘Little Kittens’
Ponytail Grass, Stipa tenuissima Volunteers, shown here, put the
Rush, Striped, Baumea rebiginos ‘Variegata’ finishing touches on a rain garden
Russian Sage, Perovskia atriplicifolia at Happy Hollow Elementary School.
Tickseed, Golden, Coreopsis tinctoria It is important to realize that a rain garden is not a water garden
or pond. Whereas a pond holds water all the time and can support
aquatic plant and animal species, a rain garden is more like a sponge.
Although water pools as runoff collects, the soil in a rain garden will
absorb it within two to four days, an important characteristic that
prevents 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 house
or on top of a septic tank drain field. Keep a ten-foot distance from
the foundation. Twenty feet is better. One common-sense rule is to
place your rain garden in line with the basic drainage pattern of your
yard, so overflow will drain away from the house.
Blazing star, Liatris The choice of plants is up to the gardener. Just be sure to con-
spicata, shown here, is sider the ability of each plant to flourish in both extreme wet and dry
a native prairie plant Great blue lobelia, Lobelia conditions. A suggested list of rain garden plants for
with deep roots which siphilitica, shown here, Northwest Arkansas can be found at the University of Arkansas
act as conduits into provides outstanding color Cooperative Extension Service’s website: http://ppc.uaex.edu/
which rain can flow. in the rain garden.
NWA_native_plants.pdf.
Shrubs Be sure to mulch the garden immediately after planting. Mulch
Butterfly Bush, Buddleia davidii acts as a sponge to capture heavy metals, oils, and grease. As the
Dogwood, Red Twig, Cornus sericea mulch decays, bacteria and plant roots have a chance to break down
Inkberry, Ilex glabra the pollutants. Mulch also retains moisture and thus benefits the gar-
Spicebush, Northern, Lindera benzoin den during a drought. Shredded hardwood works particularly well in
Spirea, Bluebeard, Caryopteris x Clandonensi rain gardens because it doesn’t float or blow away.
Planting a rain garden may seem like a small thing, but if you cal-
Trees culate the amount of rain that runs off your roof, you probably will be
Ash,Green, Fraxinus pennsylvanica surprised. Did you know that one inch of rain over one acre equals
Ash,White, Fraxinus americana more than 27,000 gallons of water?
Blackgum, Nyssa sylvatica Keeping rain where it falls by directing it into an attractive rain
Elm, Ulmus glabra ‘Camperdownii’ garden is a natural solution. You not only get a garden out of it, but
Magnolia, Sweet Bay, Magnolia virginiana you also protect our rivers, streams and lakes from pollution and mit-
Arkansas Gardener
Maple,Red, Acer rubrum igate the effects of drought. Thereby any gardener can become part of
Redbud, Cercis canadensis a beautiful solution to water runoff!m
Serviceberry, Amelanchier arborea
Sweetgum, American, Liquidambar styraciflua Joyce Mendenhall is a Master Gardener who gardens in Fayetteville. She
Witch Hazel, Hammamelis virginiana designed the four Seven Hills Supportive Housing facility’s rain gardens,
Yaupon Holly, Dwarf, Ilex vomitoria ‘Nana’ which feature plants that serve as butterfly host plants and nectar sources.
44 w w w. a r k a n s a s g a r d e n e r. c o m