horsley witten group, inc. public workshop vegetation management and maintenance january 19, 2011...

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Public WorkshopVegetation Management and

MaintenanceJanuary 19, 2011

Rhode Island Stormwater Design and Installation Standards Manual

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Introduction

• Plant Design

• Plant Selection

• Plant Care

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

• 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

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Planting Plan

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Scheduled Maintenance

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

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

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

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

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

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

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

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

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

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

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

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

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Mowing

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Mowing

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Weeding• Why Weed?

– Control invasive plants

– Promote native non-invasive plant growth

• When to weed?– April thru

October– Monthly

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

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/

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Weeding• Be on the lookout for these invasive species:

Oriental Bittersweet

Japanese Knotweed

Photo by Betty Ann Kelly

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Weeding• Be on the lookout for these invasive species

Multiflora Rose

Scotch Thistle

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

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

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Disease and Pest Control• Monitor plants for

damage

• Pesticides should be avoided

• Adopt an Integrated pest management approach– Biological– Physical– Mechanical– Cultural – Chemical controls

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

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?

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

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

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

The first Rain Garden in Virginia, located in a turning circle in front of St. Stephens School,

Alexandria.

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

St. Stephens Rain Garden- 5 years later.

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

2000

2003

It doesn’t takelong

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Fertilizing• Fertilization should

not be necessary

– Compromises pollutant reduction effectiveness

– Leads to weak plant growth

– Promotes disease and pests

– Inhibits soil life

Horsley Witten Group, Inc.Horsley Witten Group, Inc.

Questions?