Kansas State University Seaton Hall Green Roof Research Project

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1 Kansas State University Seaton Hall Green Roof Research Project Lee R. Skabelund (ASLA, KSU LARCP) March 2012 Few studies have rigorously assessed the long term viability of native plants on green roofs and their accompanying influence on soils and stormwater management. KSU Research Partners: Mary Knapp & Carol Blocksome (Agronomy), Stacy Hutchinson (Bio Systems Engineering), Rhonda Janke (Horticulture) with support from Dea Brokesh & Jeremy Merrill (Landscape Architecture) Green Roof Partially Funded by USEPA/ Kansas Dept. of Health & Environment $5,000 WaterLINK Water Quality Restoration & Protection Service Learning Mini Grant

2 My bigger question: Can we create very low maintenance and very low irrigation green roofs using native grasses and forbs? If so, we can create greater biodiversity, support essential regional pollinators, likely reduce stormwater runoff, and offer other environmental & aesthetic values (more so than using well tested sedums).

3 North American green roof developers frequently plant green roofs with Sedum spp. while ignoring local plant communities (Sutton, et.al. 2011, 5). [D]rought tolerant native and introduced herbaceous plants can be effectively used on green roofs, but may be best suited on deeper substrates [approximately 4 inches or 10cm] with some provision for irrigation. More research is needed to determine specific species success and under what specific green roof environmental parameters (Sutton, et.al. 2011, 3). MacDonagh et al. (2006, 2) connect habitat templates to green roofs noting, An estimated 10,000 years of plant selection have led to a suite of dry plant communities on cliffs, bedrock, eskers, kames, and scree beds that are adapted to harsh growing conditions similar in many ways to conditions found on extensive green roofs: hot, dry, windy environments with shallow, free-draining soil profiles. (as quoted in Sutton, et.al. 2011, 4). PRAIRIE-BASED GREEN ROOFS: LITERATURE, TEMPLATES, AND ANALOGS R.K. Sutton, J.A. Harrington, L.R. Skabelund, P. MacDonagh, R.R. Coffman & G. Koch Nov paper accepted by the Journal of Green Building for publication in MacDonagh, P., N. Hallyn, and S. Rolph Midwestern USA plant communities + Design = Bedrock Prairie Greenroofs in the Proceedings of the 4th Annual Greening Rooftops for Sustainable Communities, Boston May 2006

4 Monterusso et al. (2005) introduced some skepticism in the green roof industry by concluding that native prairie plants from Michigan, particularly grasses, were unable to succeed on extensive green roofs without supplemental irrigation during hot, dry periods. Their study found that after ceasing irrigation during mid-summer, the major growth period for warm-season or C4 grasses, many native species declined relative to Sedum spp. The C4-cycle adapts [many native] grasses to dry environments providing for higher rates of CO2 fixation at higher light intensities and temperatures but with lower transpiration rates. Many grassland forbs have alternative mechanisms for high tolerance to sun, heat and drought including extensive roots and above-and-below-ground water storage organs. The Monterusso et al. study eliminated irrigation during the second year [and] did not take into consideration that most prairie grasses and forbs require several years to establish supportive root systems (Schramm 1990). Additionally, Dvorak and Volder (2010) suggest that the 7.5 cm media depth in which Monterusso et al. (2005) planted the prairie grasses was inadequate. Source: Sutton, et.al. 2011, 5 Monterusso M., Rowe, D. & Rugh, C., Establishment and Persistence of Sedum spp. and Native Taxa for Green Roof Applications. HortScience 40: Schramm, P., Prairie Restoration: A Twenty-five Year Perspective on Establishment and Management in the Proceedings of the 12th North American Prairie Conference; Smith, D. & Jacobs, C., eds. Aug Cedar Falls, IA: Univ. of Northern Iowa. Pp Dvorak, B., Volder, A., Green Roof Vegetation for North American Ecoregions: A Literature Review Landscape and Urban Planning 96:

Green roofs with prairie and grassland plants are currently being used

[Thus], it is important to understand how they are performing and what

This will only happen with rigorous evaluation of a sufficient number

5 Green roofs with prairie and grassland plants are currently being used widely on green roofs in North America. [Thus], it is important to understand how they are performing and what we do not know about their futures. This will only happen with rigorous evaluation of a sufficient number of long-term, detailed, replicated green roof studies and trials (Sutton, et.al. 2011, 23, emphasis added). Source: Sutton, et.al. 2011, 34 Bob Grese green roof - Ann Arbor, MI established in 2004, removed as sod blocks for roof repairs in 2007, impacted by severe drought in summer 2011

6 Seaton Hall West Wing green roof location

7 The primary goal for the Seaton Hall Green Roof project is to test the viability and growth of native grasses and forbs on a small integrated green roof with a soil profile of four to seven inches, thus providing valuable information for facilities O&M.

8 The Seaton Hall Green Roof faces south and receives reflected light off windows and limestone (esp. spring and fall) sedum edge native Flint Hills Eco-region species within the center 5/31/10

9 Seaton Hall Green Roof Monitoring Summer Air Temperatures Maximum air temperatures on south end of green roof (May 20-Aug 5) Source: Mary Knapp

10 Initial Research Questions: Can native Flint Hills Prairie plant species survive on a non-irrigated green roof in Manhattan, Kansas? If so, for how long and under what conditions? How long should the establishment period be?

11 Research Design (Planting Plan) Plant 305 SF Green Roof in May 2009 with plugs: three primary species of grasses (96 plugs) in north-south rows in varying soil depths, Prairie Dropseed (4 plugs), a selection of 11 forbs (100 plugs), including a forb-like shrub (Jersey Tea), and four species of sedum (along the edges).

12 6/4/09, 6:00PM 7/14/09, 12:25PM 9/24/09, 8:30AM Seaton Hall Green Roof 2009 all photos by Lee R. Skabelund

13 Seaton Hall Green Roof May 2009 Plantings Common Name Scientific Name Amt Planted (5/19/09) Grasses (three primary species) 133 Side-oats grama Bouteloua curtipendula 32 (one row of 16 on each side of roof) Blue grama Bouteloua gracilis 64 (two rows of 16 on each side of roof) Little bluestem Schizachyrium scoparium 32 (one row of 16 each side of roof) Prairie dropseed Sporobolus heterolepis 4 (two on each side of roof NE & NW) Indian grass Sorghastrum nutans 1 (with western-most Sporobolus plug) Forbs (w/one forb-like shrub) 100 Purple poppy-mallow Callirhoe involucrata 8 (4 on each side) New Jersey tea Ceanothus americanus 8 (2 on east; 6 on west) Purple prairieclover Dalea pupurea 24 (12 on each side) Tall gayfeather Liatris aspera 8 (4 on each side) Dotted gayfeather Liatris punctata 8 (3 on east; 5 on west) Prairie coneflower Ratibida columnifera 8 (all on west side) Gray-headed prairie coneflower Ratibida pinnata 8 (all on east side) Wild blue sage Salvia azurea 8 (all on west side) Rigid goldenrod Solidago rigida 8 (all on west side) Smooth aster Symphyotrichum leave / Aster laevis 8 (2 on east; 6 on west) Common spiderwort Tradescantia ohiensis 4 (all on east side SE end) Native plants purchased from Kaw River Restoration Nurseries (Kansas grown) Sedum (four varieties planted along edges of green roof soils; Yellow Stonecrop (Sedum Kamtschaticum) selected by LRS; other sedum donated by American Hydrotech (from Northwest Horticulture in Mt. Vernon, Washington); precise quantity unknown (approx. 200); some were stuck together and thus planted in bunches Total native plants 233

Seaton Hall Green Roof - May 19, 2009 Planting Plan (dominant grasses) Sedum edge three species donated (from Pacific Northwest) 16 Sedum Kamtschaticum selected &

14 Seaton Hall Green Roof - May 19, 2009 Planting Plan (dominant grasses) Sedum edge three species donated (from Pacific Northwest) 16 Sedum Kamtschaticum selected & planted by LRS 3-4 inch soil 4-6 inch soil Blue grama (4 rows) 6-7 inch soil Little bluestem Side-oats grama (2 rows each) Native grasses & forbs (on 4-7 inch soils in middle)

15 Research Design (Irrigation/Watering Plan) Irrigate during first two growing seasons, then vary watering treatments as follows: do not water west side of roof in 2011; limit watering of entire green roof in (two options being considered: 1) no supplemental water; 2) supplemental water provided when plants are stressed).

16 Research Design (Observations & Data Collection) Observe plant survival and growth over a five-year period. Document survival and growth attributes for 27 Hairy grama, 10 Little bluestem, 10 Side-oats grama, 4 Prairie dropseed, and each species of forb. Note survival and spread of sedums.

17 Research Design (Observations & Data Collection) Record selected climatic & soil data. Collect data on air, surface & sub-surface soil temperatures, precipitation, wind, relative humidity, stormwater runoff & water quality, soil attributes. Document other observations. volunteer plants, fauna, seasonal changes & aesthetics

18 Seaton Hall Green Roof Temperature Sensor Plan 1 temperature sensor (S11) w/6-inch soils (2011) 4 temperature sensors (S1-S4) w/6-inch soils S8 1 temperature sensor (S10) w/4-inch soils 3 temperature sensors (S5-S7) w/4-inch soils S9 Sensors S1-S10 installed in 2009

19 Seaton Hall Green Roof Monitoring Equipment Photos taken on 5/31/10 Eyes, camera, ruler, notebook Solar charger connected to data logger Asphalt and gravel roof temperature sensor Tipping bucket and manual rain gauges Air temperature, wind and humidity sensors Green roof temperature sensors

20 July 27, All grasses show life above ground on the green roof. Aug 12, 2011 why the brown-out on much but not all of the west side?

In 2011, most native prairie species on non-irrigated west side of GR browned out (too early to tell if they are dead as greening of some plants occurred late summer and fall, and not everything had

21 In 2011, most native prairie species on non-irrigated west side of GR browned out (too early to tell if they are dead as greening of some plants occurred late summer and fall, and not everything had greened up as of March 26, 2012). On west side, Sedum survived very rigorous temperatures (more than 20 days above 100F) in 3-4 inches of soil. Seven Bouteloua gracilis on four-inch soils on the southwest part of the green roof survived the summer of 2011 (six set seed). Given that this is an integrated green roof it is possible that subsurface water influences growth and survival on the west side. Surface temperatures in two locations of the southwest quadrant were frequently in the F range, with temperatures of over 150F recorded on several days in July & August (Sources: observations by Skabelund & Blocksome in 2011 and Skabelund in 2012; summer 2011 data-logger record.)

22 Hottest Temperature Readings on Green Roof for 2011: Air temp at south end of roof F on 8/2/11 & 110.4F on 7/24/11 Surface temp above 6-inch soil near SE end of GR F (1:00pm) on 7/17/11 Surface temp above 6-inch soil near SW end of GR F on 7/18/11 & on 7/24/11 Sub-surface temp at base of 6-inch soil noted above (near SW end of GR) F on 2:55pm, warmed to 108.3F by 5:15pm 100.5F on 1:45pm, warmed to 107.5F by 5:40pm Surface temp near SE end of green roof F** (2:10pm) on 7/24/11 Air temp at south end of green roof F (2:10pm) on 7/24/11 Surface temp on silver roof F (2:10pm) on 7/24/11 Surface temp on asphalt & gravel roof F (2:10pm) on 7/24/11 Surface temp near SW end of green roof * & 152.0F** (2:10pm) on 7/24/11 * above 4 soils; ** above 6 soils // dense prairie vegetation // sparse vegetation July 2011 Rainfall Notes (lrs): After an early morning rain event (0.97 ) on 7/7 no substantial rain fell on the green roof again until 7/24 (evening). Due to visible stress, prairie plants on the east side of the green roof were hand watered four times during this July 2011 dry period.

2011 Findings & Reflections (after three growing seasons) Plant vigor and survival related to the Seaton Hall Green Roof: 14/56 forbs on the west side (not irrigated in 2011) alive All 14 of these

23 2011 Findings & Reflections (after three growing seasons) Plant vigor and survival related to the Seaton Hall Green Roof: 14/56 forbs on the west side (not irrigated in 2011) alive All 14 of these plants (representing six different species) were near middle of roof, where they may have tapped into soil moisture due to east side irrigation during dry periods. 2 of 8 west side forbs died out (Aster laevis and Ratibida columnifera) during /31 forbs on the east side (plus at least eight Aster laevis recruits) alive 3 drought-tolerant Liatris aspera died out on east side (perhaps due to fierce competition for light and/or moisture). 5 other species had at least two plants survive in Native grasses are doing very well in hand-irrigated media on the east side, but are generally doing poorly on west side (not irrigated in 2011 which was very hot July to September, and included several dry spells of over seven days).

24 2011 Findings & Reflections (after three growing seasons) Plant vigor and survival related to the Seaton Hall Green Roof: Schizachyrium scoparium (Little Bluestem) 7/16 alive on west side (five look to be in reasonable shape) 16/16 alive on east side Bouteloua curtipendula (Side-oats Grama) 3/16 alive on west side (only #16 at the sw end looks to be in good shape) 16/16 alive on east side Bouteloua gracilis (Blue Grama) 23/32 alive on west side (16/16 alive in the center of the roof, typically in deeper soils and in close proximity to the east side which was watered) 30/30 alive on east side (south end plants along edge of the east side beginning to be buried by Little Bluestem / Schizachyrium scoparium)

shallow 3-4 inch soils along edges of east side of roof.

where they typically receive more protection from elements.

25 2011 Findings & Reflections (after three growing seasons) Plant vigor and survival related to the Seaton Hall Green Roof: Recruitment of young grass seedlings (esp. Schizachyrium scoparium) on east side of green roof abundant & intermixing in shallow 3-4 inch soils along edges of east side of roof. Schizachyrium scoparium seedlings also present along NW face of building where they typically receive more protection from elements. Recruitment of Bouteloua curtipendula & Bouteloua gracilis also happening on both sides of the roof. Photos taken 10/18/11 (left), 7/25/11 (center), and 7/7/11 (right) along east side.

Experimental Plants on the Seaton Hall Green Roof: Sporobolus heterolepis (Prairie Dropseed most common in the upper midwest in mesic prairies, but also occurs on dry, rocky prairies) 3 of 4 alive

26 Experimental Plants on the Seaton Hall Green Roof: Sporobolus heterolepis (Prairie Dropseed most common in the upper midwest in mesic prairies, but also occurs on dry, rocky prairies) 3 of 4 alive (one, on west side near the center, was 73 cm tall and had 22 flowering stalks in Oct likely able to tap into irrigation water on the east side of the green roof; no flowering stalks present on two plants on east side, perhaps due to competition from nearby grasses). Solitary Prairie Dropseed (east of browned-out Little Bluestem and Sideoats Grama) in NW Quad, 10/25/11

in moist places, on sandy, rocky, or clayey soil) 4 of 4 alive on SE corner, surrounded by

27 Experimental Plants on the Seaton Hall Green Roof: Tradescantia ohiensis (Common Spiderwort most common along roadsides and in meadows, thickets, prairies, open woods or disturbed areas; typically in moist places, on sandy, rocky, or clayey soil) 4 of 4 alive on SE corner, surrounded by Schizachyrium scoparium). Common Spiderwort surrounded by Little Bluestem and other grasses in SE Quad, 7/25/11

28 Response of Vegetation to Different Treatments: In 2011, the west side of the green roof was not irrigated and most grasses and forbs browned out. 34* of 67 grasses on the west side (alive in Oct. 2010) showed life above ground while all 64 irrigated grasses on the east side were still living in Oct ** 14 of 62 forbs on the west side (alive Oct. 2010) showed life above ground while 25 of 37 forbs on the east side were still living in Oct * 16 of these were along the center of the roof. ** As of 3/27/12 these findings seem to still hold true.

Seaton Hall Green Roof Monitoring Plant Survival & Growth: (2011) Plant survival documented on 10/25/11 by Skabelund, Blocksome & Merrill Common Name Scientific Name Amt (10/25/11) Amt (7/2/10)

(16E; 16W) Prairie dropseed Sporobolus heterolepis 3 (2E; 1Wc) 4 (2E; 2W) Indian grass Sorghastrum nutans 0W 1W (with Sh) Forbs 39 + 8 98 + 1 Purple poppy-mallow Callirhoe involucrata 6 (4E; 2Wc) 8

29 Seaton Hall Green Roof Monitoring Plant Survival & Growth: (2011) Plant survival documented on 10/25/11 by Skabelund, Blocksome & Merrill Common Name Scientific Name Amt (10/25/11) Amt (7/2/10) Grasses Side-oats grama Bouteloua curtipendula 19 (16E; 3W) 32 (16E; 16W) Blue grama Bouteloua gracilis 53 (30E; 23W) 62 (30E; 32W) Little bluestem Schizachyrium scoparium 23 (16E; 7W) 32 (16E; 16W) Prairie dropseed Sporobolus heterolepis 3 (2E; 1Wc) 4 (2E; 2W) Indian grass Sorghastrum nutans 0W 1W (with Sh) Forbs Purple poppy-mallow Callirhoe involucrata 6 (4E; 2Wc) 8 (4E; 4W) New Jersey tea Ceanothus americanus 0E/W 8 (2E; 6W) Purple prairieclover Dalea pupurea 15 (11E; 4Wc) 24 (12E; 12W) Tall gayfeather Liatris aspera 4 (2E; 2Wc) 7 (3E; 4W) Dotted gayfeather Liatris punctata 1 (0E; 1Wc) 8 (3E; 5W) Prairie coneflower Ratibida columnifera 0W 8W Gray-headed prairie coneflower Ratibida pinnata 3E 7E Wild blue sage Salvia azurea 2Wc 8W Rigid goldenrod Solidago rigida 3Wc 9W Smooth aster Symphyotrichum leave / Aster laevis 2E + 8E (seedlings); 0W 8 (2E; 6W) Common spiderwort Tradescantia ohiensis 3E 4E Sedum - three species still present on the green roof, with Sedum Kamtschaticum (Yellow Stonecrop) clearly doing the best along all edges and the ground-hugging sedum doing well where it is growing in the shade of native grasses. Total native plants f + >100 g f +? g

30 Oct. 22, 2010 end of 2nd growing season NW Quad (all grasses alive on west side) All 67 grasses show life above ground Oct. 25, 2011 end of 3rd growing season NW Quad (west side not irrigated in 2011) 34 of 67 grasses show life above ground

31 Aug 13, 2010 All grasses documented as living at the end of 2009 still show life above ground on both east & west sides. Aug 12, 2011 All grasses show life above ground on east side; ~50% of grasses on west side show life.

32 Selected References: Berghage, R. & W. Hunt, et.al Quantifying Evaporation and Transpirational Water Losses from Green Roofs and Green Roof Media Capacity for Neutralizing Acid Rain. Center for Green Roof Research, Penn State University. Dvorak, B. & A. Volder Green roof vegetation for North American ecoregions: A literature review. Landscape and Urban Planning 96: Getter, K.L. & D.B. Rowe The Role of Extensive Green Roofs in Sustainable Development. HortScience 41(5): Glass, C.C ASLA Green Roof Water Quality and Quantity Monitoring. Washington, DC. Kurtz, et.al Stormwater Management Facilities Monitoring Report: Sustainable Stormwater Management Program. Environmental Services. Portland, Oregon. Monterusso, M., Rowe, D., Rugh, C., Establishment and Persistence of Sedum spp. and Native Taxa for Green Roof Applications. HortScience 40: Oberndorfer et al Green Roofs as Urban Ecosystems: Ecological Structures, Functions, and Services. BioScience Nov. 07 / 57(10): Simmons, et.al Green roofs are not created equal: the hydrologic and thermal performance of six different extensive green roofs and reflective and non-reflective roofs in a sub-tropical climate. Urban Ecosystems 11: Snodgrass, E. & L. Snodgrass Green Roof Plants. Portland, Oregon: Timber Press. Sutton, R.K Media modifications for native plant assemblages on green roofs. In: Sixth Annual Greening Rooftops for Sustainable Communities Conference Proceedings.

33 Acknowledgements: A WaterLINK (Water Quality Restoration and Protection Service Learning Mini-Grant awarded to KSU by the Kansas Department of Health & Environment utilizing USEPA funds) provided $5,000 in financial assistance for the Seaton Hall Green Roof Project. Following Fall 2007 design work by Professor Skabelund s LAR Specialization Studio and Spring 2008 work by seven of Prof. Skabelund s NRES students on two green roof proposals for Seaton Hall, Professor Todd Gabbard (Architecture) collaborated with Prof. Skabelund to develop a plan for implementing a demonstration green roof at Seaton Hall during Fall Two architecture students, Michael Knapp and Mark Neibling, completed detailed green roof plans for a green roof atop the third-floor breezeway, while a horticulture student researched possible plants for the roof. In Spring 2009, landscape architecture student, Mike Weber, prepared a digital planting plan for the green roof, using Prof. Skabelund s sketch plan. In total, this design-build and research project has engaged more than 30 KSU students from at least nine different disciplines, including: Landscape Architecture, Architecture, Biological & Agricultural Engineering, Architectural Engineering & Construction Science, Horticulture, Biology, Agronomy, Park Management, Agriculture Communications). Special thanks go to KSU faculty Sutton Stephens, Dennis Law, Stacy Hutchinson, Mary Knapp, Carol Blocksome, Rhonda Janke, Ed & Dea Brokesh, Melanie Klein, Jeremy Merrill, KSU Facilities staff Bob Williams, Mark Taussig, Ed Heptig, Abe Fattaey, Mark Loberg, Roof Shop personnel, and many others as well as Danker Roofing, American Hydrotech (esp. Bill Schaefer), Derbigum (esp. roofing materials representative Kathy Hogarty), BNIM (esp. Greg Pfau), Jeffrey L. Bruce LLC, and other private suppliers. KSU-Facilities, KSU-CAPD, Danker Roofing, American Hydrotech, and Derbigum each provided substantial donations.

34 Seaton Hall Green Roof 2011 lrs April 2 nd to November 9 th

Semi-arid Green Roof Research : Resilience of Native Species

Session Number 5R Semi-arid Green Roof Research 2009-2014: Resilience of Native Species Lee R. Skabelund 1 and Carolyn Blocksome 2, Dede Brokesh, Hyung Jin Kim, Mary Knapp, and Maryam Hamehkasi Kansas