Rain Garden Guide

Rain gardens are beautiful, functional landscape features that capture stormwater runoff and filter it naturally. They protect waterways while creating habitat for pollinators and wildlife.

What is a Rain Garden?

A rain garden is a planted depression designed to capture rainwater from roofs, driveways, and lawns. Water soaks into the ground slowly, filtering pollutants and recharging groundwater.

Benefits

• Reduces stormwater runoff by 30%+
• Filters pollutants naturally
• Recharges groundwater
• Creates pollinator habitat
• Beautiful, low-maintenance landscaping
• Reduces flooding and erosion

Site Selection

• At least 10 feet from buildings
• Downhill from water source (roof, driveway)
• Not over septic systems or utilities
• Full to partial sun preferred
• Level or gently sloping area
• Soil that drains (test with a perc test)

Sizing Your Rain Garden

Size depends on the drainage area and soil type:

• Sandy soil: 20-30% of drainage area
• Loamy soil: 30-40% of drainage area
• Clay soil: 50-60% of drainage area (or heavily amend)

Example: 1,000 sq ft roof with loamy soil = 300-400 sq ft rain garden

Construction Steps

1. Mark the area: Outline with string or paint
2. Dig the basin: 4-8 inches deep, flat bottom
3. Create berm: Use excavated soil for downhill edge
4. Amend soil: Mix in compost for better drainage
5. Add inlet: Channel or pipe from water source
6. Plant: Use native plants suited to wet/dry conditions
7. Mulch: 2-3 inches of shredded hardwood

Plant Selection

Center (Wettest Zone)

• Blue flag iris
• Cardinal flower
• Sedges
• Swamp milkweed

Middle Zone

• Black-eyed Susan
• Joe-Pye weed
• New England aster
• Switchgrass

Edge (Driest Zone)

• Little bluestem
• Purple coneflower
• Butterfly weed
• Wild bergamot

Maintenance

• Year 1: Water during dry spells, weed regularly
• Ongoing: Remove sediment from inlet, refresh mulch annually
• Spring: Cut back dead plant material
• Fall: Leave seed heads for birds