grasses & sedges: focus on function and design 1 · ‐allan armitage. greenhouse grower,...
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7/9/2015
Grasses & Sedges: Focus on Function and Design 1
Green InfrastructureHarness the Power of Grasses & Sedges
Shannon Currey, Marketing DirectorHoffman Nursery, Inc.Cultivate’15 • July 13, 2015
Photo: Stephen H. Blake, P.E., Artifex Environmental Design, Inc.
Hoffman Nursery, Inc.Specializing in ornamental & nativegrass liners for the wholesale trade
Rougemont, North Carolina
Overview
• Emerging field offers opportunities
• What kinds of plants make sense?
• Examples of projects and plants
• Areas where info is needed
• Next steps
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GREEN INFRASTRUCTURE
An Emerging Field for the Green Industry
• We could be growing more plants that would work
• Previously focused more on ornamental value
• Need to look at functionality, too
Horticultural economist Dr. Charlie Hall calls green infrastructure a game changer for our industry.
“We’ve got to emphasize the economic benefits, the environmental/ecosystem service benefits, and the health and well‐being benefits [of plants], not just the fact that they’re pretty.”
“What’s the Next Industry Game Changer?”Grower Talks, July 2015
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Survey: Plants in Green Infrastructure (GI)
• At 2014 NC Low Impact Development Summit, surveyed LID/GI practitioners
• Respondents indicated plants play a major role in LID/GI
• Difficulties to overcome in realizing the full potential of plants for LID/GI.
“Growing the Urban Landscape Market,” American Nurseryman, Nov. 2014
GI Features Used Most
Bioretention 88%
Vegetated swales 66%
Wetlands 57%
Wet detention 49%
Infiltration 46%
Photo: EPA
“Growing the Urban Landscape Market,” American Nurseryman, Nov. 2014
Difficulties with GI Features
Maintenance 57%
Plant survival 54%
Weeds 48%
Infiltration 35%
Plant appearance 34%
Public complaints 34%
Media/mulch 34% http://nemonet.uconn.edu/
“Growing the Urban Landscape Market,” American Nurseryman, Nov. 2014
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North CarolinaMuseum of Art
Raleigh, NCPond Project
Photo: Stephen H. Blake, P.E., Artifex Environmental Design, Inc.
2 years after planting
5 years after planting
Who Specifies Plants?
Landscape Architect 67%
Engineer 39%
Horticulturist 19%
Landscape Designer 16%
Contractor 9%
“Growing the Urban Landscape Market,” American Nurseryman, Nov. 2014
GI: An Emerging Field
• Guidelines still in development
• Recommendations and methodology inconsistent
• Plant lists are limited
• Design of features depends on water quality goals of the project and conditions at the site
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GRASSES, SEDGES, AND RUSHES
A Quick Recap
True Grasses
• In the Poaceae family
• Widest distribution of all flowering plant families
• Adapted to survive in extreme conditions
• Highly efficient, fibrous root systems
• Many maintain their habit when dormant
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Panicum virgatum
Photos: The Land Institute
Andropogon gerardii
Sedges• Mostly in the genus Carex
• Distributed throughout the world
• Many native sedges do best in organic soils with adequate moisture
• Range from shade loving to sun tolerant
7/9/2015Great Grasses for Southern Landscapes
Rushes
• In the genus Juncus
• Typically inhabit wet or moist places
• Evergreen in many climates
SELECTING PLANTS
What kinds make sense?
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What to Consider?
Soil conditions
• Improve drainage
• Prevent erosion
• Thick crowns and/or rhizomatous growth
• Continues to function during dormancy
What to Consider?
Moisture availability
• Grasses often need good drainage, especially in winter
• Sedges species have a wide range
• Minimize water use, but readily take up water when present
Ph
oto
: Ste
ph
en
H.
Bla
ke, P
.E.,
Art
ifex
En
viro
nm
en
tal D
esi
gn
, In
c.
What to Consider?
Sun exposure
• Most grasses do best in full sun
• Some sedges tolerate or even prefer shade
• Dependent on region
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What to Consider?
Contribution to plant community
• Pioneer species
• Form a matrix for other perennials
• Native species provide shelter, food, and nesting sites for wildlife
• Seasonality
What to Consider?
Tolerance for pollutants
• Metals, phosphorus, nitrogen
• Salt tolerance in colder climates
Phytoremediation potential
• Hydrocarbons (from fossil fuels)
• Metals
FOCUS ON FUNCTION
Examples of GI projects & plants
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Bioretention/Rain Gardens
• Typically shallow, vegetated depressions
• Provide storage, evapotranspiration, and treatment of runoff
• Store water and drain within 24‐48 hours
• Will dry out when rain is sparse
Bioretention &Rain Gardens
• Plants should be able to handle both wet and dry conditions
• Tolerate pollutants from surrounding land use
• Site often divided into zones – choose plants according to zones
Diagram Excerpt: http://www.svrdesign.com/
• Lowest: plants will experience standing water & fluctuating water levels
• Middle:mainly fluctuating water levels
• Upper: usually drier; upland species can do well
LowestMiddleUpper
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NCMA Pond Project
• Lower
– Juncus effusus
– Carex stricta
– Scirpus cyperinus
• Middle– Panicum ‘Northwind’
– Spartina bakeri
• Upper– Schizachyrium scoparium
– Panicum ‘Shenandoah’
– Sorghastrum nutans
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Juncus effususCommon Rush
Vase shape adds structure
Wide distribution – found throughout North America
Wildlife cover; nesting sites for birds; food for birds, mammals & caterpillars; pollen for pollinators.
Throughout N. America
Adapts to a wide range of habitats & soil textures
Can spread and naturalize
Wildlife cover; nesting sites; food for birds & caterpillars.
US
DA
Pla
nts
Dat
abas
e
Carex vulpinoideaFox Sedge
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Cool season grass
Tolerates varying soil types and pH ranges
Throughout upper East Coast, Midwest, Western US & Canada
Nesting sites; food for caterpillars, birds & mammals
Deschampsia cespitosaTufted Hair Grass
Throughout Eastern North America
Thrives in wet areas
Showy seed heads
Tolerates light shade
Carex grayiGray’s Sedge
Panicum virgatum & cvs.
• Native to prairies, open woods & brackish marshes in N. America
• Heat and drought tolerant
• Hardy to Zone 4
• Adapt to a wide variety of conditions
• Food, cover & nesting sites for birds; cover for small mammals
Switchgrass
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Schizachyrium scoparium & cvs.
• Native bunchgrass of prairies and open woods in North America
• Tolerates a wide range of soil conditions
• Striking fall color and luminous inflorescences
• Food for birds, mammals & caterpillars; cover for birds & small mammals; nesting sites; pollen for pollinators
…I expect to see Little Bluestem appear far more on landscape drawings in the future.
‐Allan Armitage
Greenhouse Grower, 1/28/15
Little Bluestem
Syme Rain GardenNC State Campus, Raleigh, NC
Syme Rain GardenNC State Campus, Raleigh, NC
Artists’ BackyardNC State Campus, Raleigh, NC
Artists’ BackyardNC State Campus, Raleigh, NC
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Indianapolis Museum of Art
Green Roofs
Plants must:
• Be heat and drought tolerant
• Provide consistent coverage
• Use nutrients efficiently
• Have non‐aggressive roots
Green Roofs
• In some regions, high rainfall with extended periods of saturation and humidity
• Select plants for high water use and drought tolerance
• Expect low fertility and shallow soil conditions
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Tolerant of high pH
Cold hardy
Adaptable
Tufted habit and fine texture
Sesleria autumnalisAutumn Moor Grass
7/9/2015Great Grasses for Southern Landscapes
Bouteloua gracilisBlue Grama
Great Plains, Southwestern US, Midwest US & Canada
Appealing seed heads
Tolerates poor soil, full sun, dry conditions
Cover; nesting sites; food for birds, mammals & caterpillars
Bouteloua gracilis ‘Blonde Ambition’
PP22048
Blue Grama
Tough, adaptable
Tolerates poor soil and drought
Abundant seed heads
Long‐lasting attractiveness
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Most of US and Canada on rocky open slopes, woodlands, and forest openings
Drought tolerant
Tolerates sandy and clay soil
Intricate, hanging flowers
Bouteloua curtipendulaSide Oats Grama
Schizachyrium scoparium cvs.
• Native bunchgrass of prairies and open woods in North America
• Tolerates a wide range of soil conditions
• May flop with shade, excess fertility, or too much moisture
• Striking fall color and luminous inflorescences
Private residence in the North Carolina mountainsPrivate residence in the North Carolina mountains
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Private residence on Kiawah Island, SCPrivate residence on Kiawah Island, SC
Swarthmore College, PennsylvaniaSwarthmore College, Pennsylvania
Photo: Jared Barnes
What’s Needed?
• Evaluation of a wider range of plants
• Phytoremediation potential of specific plants
• Optimum sizes for planting
• Optimum planting density
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Rain Garden Research at NC State Univ.
• Vegetation significantly affects remediation.
• Species and cultivar selection affect the level of sequestration.
• Plant diversity allows for more remediation to occur.
Pho
to:
Hel
en K
raus
Evaluation
Charlotte Brody Discovery GardenSarah P. Duke Gardens
Durham, NC
Charlotte Brody Discovery GardenSarah P. Duke Gardens
Durham, NC
• Sustainable Sites Initiative Pilot Project
• Case Study Investigation funded by Landscape Architecture Foundation
Suggestions for Growers
• Research and identify plants you’re growing or could grow that would fit
• Expand offerings if it makes sense
• Check back in with projects to get feedback
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Suggestions for Landscape Contractors
• Get training in GI installation and maintenance
• Work closely and early with plant supplier
• Act as bridge between grower and designer
Suggestions for Design Professionals
• Use suppliers as a resource
• Communicate frequently and convey project parameters
• Work closely and early with contractors and plant suppliers
Photo: EPA
Landscape Architecture, May 2015When the market emerges, and when the products the market needs for sustainable landscaping are ready, the landscape architecture profession should be ready to go...knowing the plants better, and working more closely with growers.
‐Carol E. Becker, Landscape Designer
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EPA Green Infrastructure Roadshow
http://epa.gov/owow/ocpd/green_infrastructure_roadshow.pdf
EPA 842‐R‐15‐002
January 2015
The Encyclopedia of Grasses for Livable Landscapes, Rick Darke, 2007, Timber Press
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The Living Landscape,Rick Darke & Doug Tallamy, 2014, Timber Press
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Conclusions
• GI projects need someone who knows the plants and can match to site conditions.
• Need partnership between designers, contractors, and growers
• We have an opportunity while the field is still developing.
Thank you for your attention!
hoffmannursery.com
www.mapyourshow.com/MYS_Shared/cultivate15/handouts/Mon_Ballroom4_GH315_Currey.pdf
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