Ornamental Grasses for Rain Gardens

Randy S. Nelson1, Esther E. McGinnis2, and Aaron Lee M. Daigh3 1University of Minnesota, Extension Educator, Clay County. 2Associate Professor, Extension Horticulturist, Sciences Department, NDSU, Fargo. 3Associate Professor of Soil Physics, Soil Science Department, NDSU, Fargo. Rain Garden

Photo: http://www3.apwa.net/Resources/Reporter/Articles/2005/9/Rain-Gardens-Strategic-puddles-for-stormwater-management

Parking Lot Downspout garden

https://stormwater.pca.state.mn.us/index.php?title=University_of_Minnesota_Arbor etum_-_runoff_model_and_rain_gardens https://emswcd.org/in-your-yard/rain-gardens/

Problem Scientific name Common name Wetland indicator status () • No scientific research on which to base Carex hystericina Porcupine sedge Obligate wetland recommendations Carex Palm sedge Obligate wetland muskingumensis • Recommendations based merely on Carex annectens Yellow fox sedge Facultative wetland wetland status Carex grayi Gray’s sedge Facultative wetland Carex brevior Plains oval sedge Facultative • Doesn’t acknowledge that rain garden Carex sprengelii Sprengel’s sedge Facultative Upland may experience drought too Carex pensylvanica Pennsylvania sedge Upland

*2-day flooding, 7-day flooding *Mild drought (15% VWC), moderate drought (10% VWC), and severe drought (5% VWC) *several cycles

1 Palm sedge 2 day flood; Plains oval sedge 2 day flood; obligate wetland plant facultative wetland plant

Control 15% VWC 10% VWC 5% VWC Control 15% VWC 10% VWC 5% VWC 1 1 1 2 1 2 3 4

Ornamental grasses Grasses used in study Wetland Common indicator Scientific name name status (Great Plains) Tufted hair Facultative Deschampsia cespitosa ‘Pixie Fountain’ Tufted hair grass grass wetland Switchgrass Little bluestem ‘Blue Photo: Randy S. Nelson ‘Northwind’ Switch grass Facultative ‘Northwind’ Heaven’ Big bluestem Facultative gerardi ‘Red October’ Big bluestem ‘Red October’ upland Chinese Facultative sinensis ‘Purpurascens’ silvergrass upland Little Facultative ‘Blue Heaven’ bluestem upland Blue grama Bouteloua gracilis ‘Blonde Ambition’ Upland grass Feather reed Calamagrostis x acutiflora ‘Karl Foerster’ Upland Blue grama grass grass Photos by Esther E. McGinnis Chinese silvergrass unless noted otherwise. Wetland indicator status, designation, and description are from Lichvar et al., 2016. Feather reed grass ‘Karl Foerster’ ‘Purpurascens’

Design Shoot mass – species x drought – 7 grass species – 2 flood durations; 2- and 7-day – 2 drought setpoints 14% (mild) and 7%(severe) volumetric water content (VWC) – Well-watered control – At least four cycles

FACW FAC FACU FACU FACU UPL UPL

2 mass – species x drought Chinese silver grass ‘Purpurascens’

14% VWC

Control 2 day 7 day FACW FAC FACU FACU FACU UPL UPL 1 1 1

Chinese silver grass ‘Purpurascens’ Visual damage rating - species

7% VWC

Control 2 day 7 day FACW FAC FACU FACU FACU UPL UPL 1 8 10

Miscanthus ‘Purpurascens’ Andropogon gerardii ‘Red October’ Purple Flame Grass Big bluestem • Red flame grass • Zone 4 • Warm season grass • 4-6’ tall • Zone 3; hardiest of the • Warm season grass Miscanthus spp. • Spectacular fall color • Reliable fall color • Clump former • Small will • Will self seed expand the width of the plant

3 Schizachyrium scoparium ‘Blue Heaven’ Panicum virgatum ‘Northwind’ Little bluestem

*Doesn’t lodge *May not be hardy in northern areas *Fall color! Zone 3; 4-5’, PPA 2014

Calamagrostis x acutiflora Bonus plant: Bouteloua gracilis ‘Karl Foerster’ ‘Blonde Ambition’ • Clump, 4-5 feet tall • Less tolerant of cyclical flooding and drought • Cool season grass than other grasses • PPA 2002 • Great for saline soils! • Hardy to Zone 3 • Can take more flooding than we expected

Photo courtesy of Walters Gardens, Inc.

‘Blonde Ambition’ Conclusion • Highly adaptable to cyclical flooding and drought • Severe drought reduced relative plant height, shoot count, total and ornamental value • May need supplemental irrigation during times of drought

• More results to come: submersion study, salt tolerance study, petroleum tolerance study

Photo courtesy of Walters Gardens, Inc.

4 Acknowledgment

• ND Specialty Crop Block Grant • Please take our survey!

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