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Public WorkshopVegetation Management and
MaintenanceJanuary 19, 2011
Rhode Island Stormwater Design and Installation Standards Manual
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Introduction
• Plant Design
• Plant Selection
• Plant Care
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• Establish a preferred design approach
• Understand site constraints and conditions
• Select appropriate plant species
• Prepare planting design plan
• Keep it simpleSource: http://plants.usda.gov
Design Basics
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Planting Plan
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Scheduled Maintenance
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Pruning and Plant Thinning• Why Prune?
– Maintain plant health and vigor
– Removal of dead or broken wood
– Encouragement of flowering and fruiting
– Control of overgrowth of plant material
Image courtesy of Rutgers New Jersey Agricultural Experiment Station
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Pruning and Plant Thinning• Trees and large
shrubs
– Wait at least 1 year– Remove dead,
damaged, or diseased branches only
– Prune in late winter/early spring
– Never prune behind the branch’s bark ridge
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Pruning and Plant Thinning• Shrubs
– Prune once the shrub approach mature height
– Immediately after flowering, unless specified otherwise
– Pruned back damaged/diseased limbs
– Do not leave stubs
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Pruning and Plant Thinning• Perennials and
grasses
– Leave dry standing stalks during dormant months
– Cut back dead foliage late winter/early spring
– Remove cut foliage from bioretention area
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Mowing
• Not necessary or recommended for raingardens/bio.
• Allow plants to flourish
• When side slopes seeded with native grass– Mow once or
twice per year
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Mowing• Use a mulching
blade or point the mower away from the bioretention area
– Fresh grass clipping are high in nitrogen
– Grass clippings can compromise pollutant removal effectiveness
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Mowing
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Mowing
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Weeding• Why Weed?
– Control invasive plants
– Promote native non-invasive plant growth
• When to weed?– April thru
October– Monthly
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Weeding• Do not use chemical
herbicides
• Remove by hand
• A list of invasive species can be found at:http://www.rinhs.org/resources/ri-invasive-species-resources/invasive-list/
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Weeding• Be on the lookout for these invasive species:
Oriental Bittersweet
Japanese Knotweed
Photo by Betty Ann Kelly
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Weeding• Be on the lookout for these invasive species
Multiflora Rose
Scotch Thistle
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Photo courtesy of Rutgers New Jersey Agricultural Experiment Station
Watering• During the first
few weeks after planting– To establish
and maintain healthy grass
• During the 1st year – Plant and grass
growth
• After the 1st year – Drought
periods only
Soaker hose
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Disease and Pest Control• Monitor plants for
damage
• Pesticides should be avoided
• Adopt an Integrated pest management approach– Biological– Physical– Mechanical– Cultural – Chemical controls
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Plant Replacement • After the first season, look for the following plant
health indicators:
Photo by Linda Brazaitis
– Was the weather drastically different than the conditions the basin was designed to retain?
– Was flow too fast through the basin, damaging health?
– Is flow being incorrectly discharged from the rain garden?
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Plant Replacement• Replace dead or
diseased plant material
• Place plant in the same location
• Re-seed the side slopes
• Best time to replant:– Early to mid Fall– Early to mid Spring
Photo courtesy of Rutgers New Jersey Agricultural Experiment Station
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The first Rain Garden in Virginia, located in a turning circle in front of St. Stephens School,
Alexandria.
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St. Stephens Rain Garden- 5 years later.
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2000
2003
It doesn’t takelong
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Fertilizing• Fertilization should
not be necessary
– Compromises pollutant reduction effectiveness
– Leads to weak plant growth
– Promotes disease and pests
– Inhibits soil life
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Questions?
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