Horsley Witten Group, Inc. Public Workshop Vegetation Management and Maintenance January 19, 2011 Rhode Island Stormwater Design and Installation Standards Manual

Horsley Witten Group, Inc. Introduction Plant Design Plant Selection Plant Care

Horsley Witten Group, Inc. Establish a preferred design approach Understand site constraints and conditions Select appropriate plant species Prepare planting design plan Keep it simple Source: Design Basics Plant Design

Horsley Witten Group, Inc. Planting Plan

Horsley Witten Group, Inc. Planting

Horsley Witten Group, Inc. Scheduled Maintenance Plant Care

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 Plant Maintenance

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 Plant Maintenance

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 Plant Maintenance

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 Plant Maintenance

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 Plant Maintenance

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 Plant Maintenance

Horsley Witten Group, Inc. Mowing Plant Maintenance

Horsley Witten Group, Inc. Mowing Plant Maintenance

Horsley Witten Group, Inc. Weeding Why Weed? –Control invasive plants –Promote native non-invasive plant growth When to weed? –April thru October –Monthly Plant Maintenance

Horsley Witten Group, Inc. Weeding Do not use chemical herbicides Remove by hand A list of invasive species can be found at: ri-invasive-species- resources/invasive-list/ Plant Maintenance

Horsley Witten Group, Inc. Weeding Be on the lookout for these invasive species: Oriental Bittersweet Japanese Knotweed Photo by Betty Ann Kelly Plant Maintenance

Horsley Witten Group, Inc. Weeding Be on the lookout for these invasive species Multiflora Rose Scotch Thistle Plant Maintenance

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 1 st year –Plant and grass growth After the 1 st year –Drought periods only Soaker hose Plant Maintenance

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 Plant Maintenance

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? Plant Maintenance

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 Plant Maintenance

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. St. Stephens Rain Garden- 5 years later.

Horsley Witten Group, Inc It doesn’t take long

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 Plant Maintenance

Horsley Witten Group, Inc. Questions?