The Townsend River Walk & Arboretum Demonstration Rainwater Garden After 2 Weeks of Planting.
The Demonstration Rainwater Garden is located next to the picnic area.
For years, the Townsend River Walk & Arboretum (TRWA) was challenged by a steep hillside on the north end of the TRWA with rainwater runoff collecting in a muddy bog, seemingly ideal for only mosquitos and weeds. To further complicate the situation with this unused area, the hillside drained from Highway 321, Lamar Alexander Parkway, with all the petroleum-based contaminants that come from a busy road eventually draining into the Little River. An impossible landscape or just the right challenge?
In 2022 the development of the Master Plan for the TRWA included installing a rain garden at the bottom of the drainage.
In Spring 2025, the timing was just right for the rain garden project. The TRWA had successfully completed an April fundraising campaign for the adjoining picnic area and the rain water garden as well as a much needed bear-proof refuse can, dog cleanup bags and refurbished restroom area. The fundraising met its goal and more! It was time to solve the roadside and rain water run-off challenge with a rain garden!
Using knowledge gained through classes. and rainwater garden articles we also used the expert guidance from the University of Tennessee Smart Yards Program. Their outstanding publication, “Rain Gardens for Tennessee: A Homeowner’s Guide”, provided the combined expertise of Engineers, Soil Scientists, Plant Scientists, and Landscape Architects and Designers, with detailed plans that guided us through every step of designing and installing a rain garden.
Being in a area with a large amount of rainfall and runoff, the rainwater garden is DIY water runoff solution that can be used by many homeowners in the all areas of Tennessee and particularly in the Townsend/Blount County area. Besides reducing runoff and erosion the plants can help filter water removing impurities and also provide animal habitat and food as well as nectar and host plants for our native pollinators.
The experts at UT summarize the benefits of rain gardens that spoke directly to our unique challenges at the TRWA. Rain gardens can:
- Slow down rainwater runoff
- Decrease potential for erosion
- Improve soil quality over time
- Decrease the need for irrigation
- Provide food and shelter for native birds and pollinators
- Help improve water quality in recreational areas
- Rely on native plants to act as a natural sponge in wet areas
The TRWA volunteers worked several mornings to shape the “bowl” area to serve as the base of the rain garden, then amended the soil with alternating layers of mulch and sand to create the “sponge”. The volunteers also installed a French drain from the new picnic area and a dry creek bed to capture runoff from the hillside above and direct it into the rain garden.
Bowl Created for the Rainwater Garden.
A berm was created at the one end with an overflow spillway the drains into the existing drain from the highway the drains into the Little River.
French Drain from Picnic Area to Rainwater Garden
The Demonstration Rainwater Garden Ready to Plant!
Layers of clay, sand and mulch to help create the proper environment of the plants and to absorb rain runoff.
Next up, was the fun of planting day, installing approximately 150 plants! The TRWA worked with local grower Miller’s Cove Native Plants for native plants that would thrive in (1) moist/wet soil, (2) sun to part shade, and (3) plants that would serve as a food source for our native pollinators.
Plants Ready for Planting in the Rainwater Garden.
Raingarden Plants Laid Out and Ready to Plant!
The Planting Begins!
The Demonstration Rainwater Garden Immediately After Planting.
Didn't look like much then but the picture at the top of this article show the results after 2 weeks and going strong.
We have put over 200 gallons of water on the garden during the last month due to the lack of rain.
Over the next few years the garden will be completely covered with native plants!
Below is a List of Plants Selected and Additional Information About Each Plant.
| Common Name |
Scientific Name |
Soil Drainage | Pollinator Information and Additional Info |
| Great Blue Lobelia | Lobelia siphilitica | Moist, Occasionally Wet |
Long probiscis pollinators: hummingbirds, butterflies, bumble bees Larval host for: Pink-Washed Looper Moth (Enigmogramma basigera), Additional Info: https://plants.ces.ncsu.edu/plants/lobelia-siphilitica/ |
| Cardinal Flower | Lobelia cardinalis | Moist, Occasionally Wet |
Attracts butterflies and hummingbirds Larval Host for: Checkered White butterfly, Spicebush Swallowtail, Additional Info: https://plants.ces.ncsu.edu/plants/lobelia-cardinalis/ |
| Narrow Leaf Sunflower | Helianthus angustifolius | Good Drainage, Moist, Occasionally Wet |
Birds consume the seeds. |
| Blue Mistflower | Conoclinium coelestinum | Moist, Occasional Flooding |
Attracts native bees, butterflies and moths. Provides abundant nectar for monarchs, swallowtails, queens, soldiers, pearl crescents, white peacocks, little yellows, and many other butterflies. |
| New England Aster | Symphyotrichum novae-angliae | Good Drainage, Moist, Occasionally Dry |
Attracts native bees, butterflies and moths. Host plant for several bee species. Larval Host for: Pearl Crescent, the Gorgone Checkerspot butterfly and the Wavy-Lined Emerald moth. Additional Info: https://plants.ces.ncsu.edu/plants/symphyotrichum-novae-angliae/ |
| Pale Meadow Beauty | Rhexia mariana | Moist, Occasionally Wet |
Attracts many pollinators especially native bees. Larval Host for: Gray Hairstreak, Additional Info: https://plants.ces.ncsu.edu/plants/rhexia-mariana/ |
| Fox Sedge | Carex vulpinoidea | Wet | Birds and small mammals consume the achenes and use the plants for cover. Attracts Butterflies Larval Host for: Several skipper butterflies and a variety of moths. Additional Info: https://www.wildflower.org/plants/result.php?id_plant=cavu2 |
| Gray's Sedge | Carex grayi | Moist, Occasionally Wet |
Birds and small mammals consume the achenes and use the plants for cover. Additional Info: https://plants.ces.ncsu.edu/plants/carex-grayi/ |
| Swamp Rosemallow | Hibiscus grandiflorus | Frequent Standing Water, Occasional Flooding, Occasionally Wet |
Attracts bees, butterflies and insects including beetles. Additional Info: https://plants.ces.ncsu.edu/plants/hibiscus-grandiflorus/ |
| Scarlet Rosemallow | Hibiscus coccineus | Moist, Occasionally Wet |
Attracts hummingbirds, butterflies and other insects including beetles. Larval Host for: Gray Hairstreak, Painted Lady, Common Checkered Skipper, Additional Info: https://plants.ces.ncsu.edu/plants/hibiscus-coccineus/ |
To further enhance the hillside above the rain garden, blueberry plants and a grape arbor were installed as well as the start of a new pollinator garden bordering the Lamar Alexander Parkway. Native Carolina Silver bells trees (Halesia carolina) were planted near the picnic area. The TRWA rain garden is complete and will mature into a beautiful addition to the picnic area with colorful blooms, swaying grasses, bees and butterflies, and hopefully cleaner runoff into the cold, clear waters of the Little River. Stop by, ask questions and watch our garden grow!
Next Part 4 of our Picnic Area/Rainwater Garden Story - The Townsend Express!
