UMass Extension Landscape, Nursery and Urban Forestry Program

Rain Gardens: A Way to Improve Water Quality in Your Community

Fact Sheet Category: 
Plant Materials: General

What are rain gardens?

When rain falls on natural areas such as a forest or meadow, it is slowed down, filtered by soil and plants, and allowed to soak back into the ground. When rain falls on impervious surfaces such as rooftops, roads, parking lots and driveways, rain does not soak into the ground and storm water runoff is created. Stormwater runoff picks up pollution such as fertilizer, pesticides, sediment, motor oil, litter, pet and yard waste. In many Massachusetts towns, stormwater runoff does not go to a treatment plant. Instead, water and the pollution in it flows directly into storm drains, which eventually can deliver these pollutants to bodies of water.

Rain gardens are attractive, functional landscaped areas designed to capture and filter stormwater before it runs off into storm drains. They collect water in natural or constructed shallow vegetated depressions and allow it to soak into the ground slowly. This reduces the potential for erosion and minimizes the amount of pollutants flowing from a yard into a storm drain, and ultimately into our waterways. They may also be used as a buffer in shoreline areas to capture runoff from the home landscape before it enters a lake, pond, river or estuary.

Line drawing of a rain gardenRain gardens use the concept of bioretention, a water quality practice in which plants and soils filter pollutants from stormwater. By reducing stormwater runoff, rain gardens can be a valuable tool to help protect our water resources. While an individual rain garden may seem like a small thing, collectively they produce substantial neighborhood and community environmental benefits.

By capturing runoff in shallow depressions and letting it soak into the ground, rainwater gardens also help recharge stores of groundwater in aquifers. Moreover, they filter out sediment and other pollutants by catching close to the first inch of runoff, which contains the highest concentration of pollutants. Rain gardens transform stormwater from a destructive carrier of pollution into a source of sustenance for plant and wildlife habitats: the plants thrive on nitrogen and phosphorus that is picked up, while their stems trap sediment. Rainwater gardens are being incorporated into many new and existing areas for their environmental benefits, as well as their natural beauty.

What makes a rain garden a rain garden?

A rain garden resembles a regular perennial garden or mixed border in many ways. It is designed with deep-rooted plants that come back year after year; it is pretty to look at; it often has lovely flowers, grasses, trees and shrubs. So what makes it different from any other perennial garden? There are certain qualities that make a rain garden unique:

  • Rain gardens have a ponding area, but they are not ponds. They often are planted with wetland plants, but they are not wetlands (although you can design a rain garden that mimics a wetland).
  • The garden absorbs and filters rain that would otherwise run off your property and down the storm drain.
  • Many of the plants in the garden might be native to the region and have extensive deep roots that help the garden absorb rain. The native plants do not need special attention once they are established. Non-native plants may be used as long as they are also non-invasive and pest free.
  • There is a bowl-shaped dip in the garden, which holds the rain while it soaks into the soil.
  • The garden bed is prepared or sometimes replaced to a depth of up to two feet in order to relieve soil compaction and make the garden able to absorb water.

A garden that does not have rain directed into it from a hard surface of your property will still be a valuable asset. However, unless stormwater runoff is directed into the garden, it is not a rain garden. In addition to reducing and filtering stormwater runoff and increasing groundwater recharge, rain gardens provide many other benefits. They provide habitat for wildlife and, with the proper selection of plants, increase the number and diversity of birds and butterflies for those who enjoy watching them. Rain gardens provide an attractive and creative alternative to traditional lawn landscapes and require less maintenance because they do not need to be mowed, fertilized, or watered once established. They may also increase property values with creative landscaping designs.

Locating the rain garden

Place rain gardens near your home to catch runoff from your roof, or farther out in your lawn to collect surface water draining across your property. Examine your yard while it is raining to discover the drainage pattern on your property. Find out where runoff flows and locate areas where water collects. If the rain does not flow naturally to your chosen spot, you can install piping underground or send the rain along a constructed channel or swale. Typically, the largest sources of runoff are rooftops, paved surfaces, slopes, and compacted soils. Some helpful tips are listed below to help you determine the best location for your rain garden:

  • Rain gardens should be a minimum of ten feet from your home and your neighbors’ homes, to prevent damage from water seepage.
  • Rain gardens should not be placed over or near the drain field of a septic system.
  • Because these areas are already poorly drained, rain gardens should not be placed in an area of your yard where water collects. They should be placed up-slope of these areas to reduce the amount of water that flows into them.
  • Sunny or partly sunny locations are best for rain gardens, but shade gardens are possible.
  • Rain gardens should be integrated with your landscape. They can have a formal or informal look based on your preference.
  • Rain gardens should not be installed under large trees. Trees have extensive root systems that may be damaged in the garden excavation process. In addition, they may not be able to adapt to the extra moisture being held by your rain garden.
  • Make yourself aware of underground service lines or utilities. Call “Dig Safe” at 1-800-344-7233 for information about underground utilities.

Consider how the rain garden will fit in the overall landscape when looking for a location. Determine if you want it near outdoor gathering places where the beauty of the plants can be appreciated. Look out of your windows to see what views the rain garden can provide. The rain garden is more than just a stormwater management tool; it will be an integral part of your landscape.

Diagram of a rain garden layoutOnce you select a location, you may decide to send additional water to this site. Use flexible plastic pipe to direct water from downspouts and collecting areas to the rain garden. Be sure to factor this additional water flow into your garden sizing calculations.

Soils and drainage

Rain gardens work best when constructed in well-drained or sandy soils, but they can also be installed on sites with less permeable soils such as clays. Your rain garden needs to be able to absorb the water coming off your roof and driveway. Sandy soils drain well, while clay soils may become waterlogged. If your soil is sandy, you may be able to simply loosen the soil and improve it with some compost to prepare your rain garden for planting. If your soil is clay, you will have more work to do. Even light clay soils may create drainage problems if a lot of water is directed to the rain garden. Soil removal and replacement may be needed if your soil is clay. The recommended soil replacement mix is 50-60% sand, 20-30% topsoil, and 20-30% compost. Be sure no clay is in your replacement soil.

You can test your soil’s infiltration rate by digging a hole 8 inches wide and 8 inches deep. Fill it with water and see how long it takes to sink in. The water needs to go down an inch per hour. If it takes longer than that, you will need to do additional site preparation to improve infiltration.

There are three signs of an impermeable soil:

  • The site ponds water or remains saturated for several days after a storm event.
  • The soil shows signs of being a wetland soil (gray soil with ribbons or areas of brown color) within 1 foot of the surface.
  • Water poured in the test hole is still there after two days, provided it has not rained.

If you see any of these signs, your garden will need to be designed as a backyard wetlands garden, or another location should be selected. Otherwise, your site is suitable for a rain garden.

How large should the rain garden be?

Rain gardens can be large or small – the size depends primarily on the site drainage area. The volume of water collected will be roughly equivalent to the amount of rain falling on impervious areas draining to the garden location, such as driveways, rooftops, and lawns (if included in the drainage area). To determine the volume of runoff to be collected, first determine the square footage of the surfaces that will provide the flow into the garden. If a gutter downspout will run directly into the garden, the only information that you will need is the area of the roof that contributes to that gutter. Measure the footprint of your house (the area taken up by your house if you were looking down from above). Then estimate how much of this area actually contributes to the gutter downspout. In other words, if it were raining, what portion of the roof area would be contributing water to the garden? Next, divide this area by 6. This calculation sizes the garden to hold one inch of roof runoff in a garden 6 inches deep. For example, suppose a house has a footprint of 60 feet x 30 feet, or 1800 ft2. One quarter of the roof area contributes to the gutter near where the rain garden is to be built. Therefore, the contributing area would be 1800 ft2 x 0.25 = 450 ft2. This area is then divided by 6, so that the square footage of the rain garden would be 450 ft2 / 6 = 75 ft2. A nicely shaped rain garden might be 10 ft x 7.5 ft. However, you have the flexibility to make it any shape you want, as long as you approximate the size. With silty soils, the size can be increased about 50%. If the soils are clayey, the size can be increased up to 100%. This increase will provide the same amount of treatment as if your soils were sandy. If you are including runoff from driveways or lawn areas, be sure to calculate the square footage and add that to the total to get the correct size needed. Once you have determined the total drainage area for your rain garden, use the following chart to determine possible rain garden dimensions. Dimensions are given for ponding depths of 6 inches and 3 inches. A good rule of thumb is that the rain garden should be about twice as long (perpendicular to the slope) as it is wide.

Drainage Area Required Size of Rain Garden
(6” deep)
Potential Rain
Garden Dimensions
(ft x ft)
Required Size of
Rain Garden
(3” deep)
Potential Rain Garden Dimensions
(ft x ft)
800 ft2 40 ft2 4x10, 5x8, 6x7 80 ft2 7x12, 8x10, 9x9
1000 ft2 50 ft2 5x10, 6x8 100 ft2 7x15, 10x10
1200 ft2 60 ft2 4x15, 5x12, 6x10, 8x8 120 ft2 10x12, 8x15
1400 ft2 70 ft2 5x14, 7x10 140 ft2 10x14, 7x20
1600 ft2 80 ft2 7x12, 8x10, 9x9 160 ft2 8x20, 10x16
1800 ft2 90 ft2 6x15, 7x13, 8x12, 9x10 180 ft2 9x20, 10x18, 12x15
2000 ft2 100 ft2 7x15, 10x10 200 ft2 10x20, 14x15
2500 ft2 125 ft2 8x16, 10x13 250 ft2 10x25, 13x20, 15x17
3000 ft2 150 ft2 10x15, 12x13 300 ft2 10x30, 15x20
3500 ft2 175 ft2 8x16, 10x13 350 ft2 14x25, 18x20
4000 ft2 200 ft2 9x20, 12x15 400 ft2 16x25, 20x20
5000 ft2 250 ft2 10x25, 13x20, 15x17 500 ft2 20x25

Installing the rain garden

Once you feel confident in the placement of the garden, lay out the shape to define where to dig. Outline the area of the proposed garden by spraying with non-toxic soccer-field paint. Another method is to lay a hose along the shape of the garden, then dig along the hose. This gives a nice flowing border to the garden area. Alternatively, you could simply choose a rectangle as the shape of your garden.

If the yard is fairly level, you can just dig out the bowl to the proper depth, which is 6 inches deep, or a couple of inches deeper if mulch will be used. If the yard is sloped, you may need to construct a small berm (mound) at the down-slope side of the garden to prevent the soil from washing away after a storm. Use the soil that was removed from the upslope side of the garden and add it to the down-slope side. The bottom of the garden should be fairly level to maintain the storage area inside the garden. Slope the edges of the garden, but do not make them too steep. Steep slopes tend to erode easily. Mulch or a ground cover will help to stabilize the soils.

If the selected area is lawn, you will have to remove the turf. Either you can use this in another area of your yard, or it can be composted to help improve your soils. If your soil drains well, simple soil preparation is all that is needed. Incorporate compost into the garden bed to improve the quality of the soil. If your soils are clay, soil replacement is probably in order. You may also want to add a reservoir of gravel at the bottom of the garden bed, or add tiles or an under-drain that leads to another area. This will avoid having your rain garden become waterlogged. The idea is to create a living sponge of soil, plants, roots and mulch, not a soggy bog.

Diagram of steps for planting a rain gardenGrade the surface of your prepared rain garden bed in such a way that the water entering it can spread out over a large flat area and soak into the soil. This may involve removing a lot of soil. When your ponding area is ready and the soil is nice and loose, it is time to plant. You can prepare a rain garden bed and then cover it with mulch until later; then, plant through the mulch. On the other hand, you can plant immediately, and then mulch the plants. The choice is yours. The sooner the plants are in, the faster your rain garden will become established.

Planting the rain garden

While rain gardens are a highly functional way to help protect water quality, they are also gardens and should be an attractive part of your yard and neighborhood. Think of the rain garden in the context of your home’s overall landscape design. When choosing plants for the garden, it is important to consider the height of each plant, bloom time and color, and its overall texture. Use plants that bloom at different times to create a long flowering season. Mix heights, shapes, and textures to give the garden depth and dimension. This will keep the rain garden looking interesting even when few flowers are in bloom. A small tree or a few flowering shrubs may be included in the rain garden if it is large enough. It is important to note that plants in a rain garden will have to tolerate fluctuating levels of soil wetness. Your rain garden will have a couple of different wetness zones in it. In the deepest part of the garden, you can put plants that withstand a couple of days of standing water at a time. In the shallower parts and on the edges, you can put more typical landscape plants. Drought tolerant plants can be planted on the perimeter. Many native plants make great candidates for the rain garden and are generally adapted to local growing conditions. Introduced ornamentals may also be used as long as they have no invasive characteristics or problem pests.

When laying plants out, randomly clump individual species in groups of 3 to 7 plants to provide a bolder statement of color. Make sure to repeat these individual groupings to create repetition and cohesion in a planting. This will provide a more traditional formal look to the planting.

Use container-grown plants with a well-established root system. Dig the hole for each plant twice as wide as the plant container and deep enough to keep the crown of the young plant right at the soil line, as it was in the container. After you put the plant in the ground, gently tamp the soil around the roots to eliminate air pockets. Water immediately after planting, and then water weekly, to a depth of several inches, until the plants are well established. After the first growing season, you should not need to water the plants unless there is a lengthy drought. Add mulch two inches thick, keeping it off the crowns of the plants. Use mulch that will not float away; hardwood mulch is best.

The following plants are some of those that are suitable for inclusion in a rain garden:

Trees
Name Exposure Moisture Mature size Bloom Comments
Acer palmatum Japanese maple Sun to part shade Moist 5’-25’ depending on cultivar Not significant Graceful small tree; green or red leaves, some with deeply dissected leaves; excellent fall color
Acer rubrum
Red maple
Sun to part shade Dry to wet 40’-60’ April Shallow root system; attractive red flowers and fruit; tolerates moist or dry sites; red/yellow/orange fall color
Betula nigra River birch Sun to part shade Dry to wet 40’ Not significant Tolerates wet feet or upland site; interesting catkins; beautiful peeling bark; yellow fall color
Carpinus caroliniana American hornbeam Part sun to shade Moist 20’-30’ May Tolerates sun if soil is moist; tolerates periodic flooding; unique fluted silver-gray bark; yellow, red, or orange fall color
Cornus kousa Kousa dogwood Sun Moist to dry 25’-30’ June/July Resistant to dogwood anthracnose; large white bracts appear after the foliage; reddish purple fall color
Magnolia virginiana Sweetbay magnolia Sun to shade Wet to moist 15’-20’ June Large white fragrant flowers; small multi-stemmed tree; red berries; semi-evergreen; will tolerate wet soils
Nyssa sylvatica Tupelo Sun Wet to dry 30’-50’ Not significant Tolerates seasonal flooding or dry, rocky uplands; blue-black berries taken by birds; brilliant scarlet fall color
Shrubs
Aronia arbutifolia Red chokeberry Sun to part shade Dry to wet 4’-10’ May/June White flowers with red stamens; bright red, edible berries persist in winter; salmon to scarlet fall color
Aronia melanocarpa Black chokeberry Sun to part shade Dry to wet 3’-5’ May/June White flowers with red stamens; black berries persist in winter; dark purple-red fall color
Callicarpa americana Beautyberry Sun to part shade Moist 3’-8’ July/August July/August
Clethra alnifolia Sweet pepperbush Sun to part shade Moist to dry 6’-8’ July/August Very fragrant white or pink flowers; yellow fall color; butterfly nectar plant
Cornus stolonifera Red twig dogwood Sun to part shade Moist 6’-8’ June White flowers; blue or white berries; red/maroon fall color; scarlet twigs in winter
Hamamelis x intermedia Hybrid witchhazel Sun Moist to dry 12’-15’ December/April Winter bloomers in yellow, red or copper; in bloom for 4 to 6 weeks; many cultivars
Hamamelis virginiana Witchhazel Sun to part shade Moist to dry 12’-15’ October Tolerates irregular flooding or dry sites; yellow fragrant strap-like flowers; yellow fall color
Hydrangea arborescens Smooth hydrangea Sun to part shade Moist to dry 3’-8’ June/July Creamy white flowers on new wood; cv. Annabelle has large flower heads; cv. White Dome is a lace-cap type
Hydrangea paniculata Panicle hydrangea Sun to part shade Moist to dry 5’-12’ July/September Large panicles of white flowers turn to pink by fall; blooms on new wood; many cultivars available
Hydrangea quercifolia Oakleaf hydrangea Sun to part shade Moist to dry 5’-8’ July Pyramidal white flower heads age to mauve; large oak-shaped leaves with deep red fall color; shaggy reddish bark is attractive
Ilex glabra Inkberry Sun to part shade Wet to dry 3’-6’ Summer Slow-growing evergreen; creamy-white flowers; tolerates wet soils; need male & female for berries
Ilex verticillata Winterberry Sun to part shade Wet to moist 6’-10’ June/July White flowers; yellow fall color; need male & female for scarlet berries; tolerates wet soil
Itea virginica Sweetspire Sun to part shade Moist 4’ May/June Fragrant white flowers; fall foliage garnet to purple
Leucothoe racemosa Fetterbush Partial shade to shade Wet to moist 4’-6’ May/June White drooping flowers; evergreen leaves turn red/purple after frost
Physocarpus opulifolius Ninebark Sun Moist to dry 8’-10’ May/June Cultivars are better than the species; ‘Diablo’ has purple foliage while ‘Dart’s Gold’ has yellow foliage; drought tolerant
Rhododendron viscosum Swamp azalea Sun to part shade Wet to moist 6’-8’ July/August Intensely fragrant white flowers; bronze fall color
Sambucus canadensis Elderberry Sun to part shade Wet to moist 6’-8’ June/July Large white flower clusters; ornamental, edible purple berries; fast-growing
Sambucus nigra European elderberry Sun to part shade Moist 10’-15’ June Larger than S. canadensis; numerous cultivars with colorful foliage
Viburnum dentatum Arrowwood Sun to part shade Moist to dry 8’-10’ May/June Creamy white flowers; blue berries; crimson fall color
Viburnum sieboldii Siebold viburnum Sun to part shade Moist to dry 10’-15’ May/June Creamy white flowers are followed by bright red berries which change to black, relished by birds
Viburnum trilobum American cranberrybush Sun to part shade Moist to wet 8’-12’ May White flowers; edible red berries; yellow-purple-red fall color
Perennials
Amsonia hubrechtii Willowleaf Bluestar Full sun to partial shade Moist to dry 18”-3’ May/June Trumpet shaped light blue flowers, delicate bottlebrush leaves give this plant an attractive, shrub-like appearance; leaves turn a beautiful yellow in fall
Andropogon gerardii Big bluestem Sun Dry to moist 3’-5’ August/September Prairie grass with purple flowers; blue-green blades turn tawny in fall; tolerant of acid soil, sandy soil, flooding and drought
Aquilegia spp. Columbine Sun to part shade Moist 2’ May/June Flowers attract hummingbirds and butterflies, elegant blue-green divided foliage
Asclepias incarnata Swamp milkweed Sun Wet to moist 2’-4’ June/July Pink blooms in midsummer; butterfly nectar plant; monarch butterfly host plant
Aster divaricatus White wood aster Part shade to shade Moist to dry 1’-3’ September/October Good for dry shade or moist woods; white flowers attract butterflies; attractive massed at woodland edge
Aster laevis Smooth aster Sun Moist to dry 2’-4’ August/October Pale blue flowers attract butterflies; mildew free
Baptesia australis Blue false indigo Sun Moist to dry 3’-5’ May/June Indigo-blue showy flowers on blue-green, compound foliage make a striking show; effect is shrub-like
Chelone glabra White turtlehead Sun to part shade Wet to moist 2’-3’ September/October White snapdragon type flowers; good fall bloomer
Chelone oblique Pink turtlehead Sun to part shade Wet to moist 1’-4’ September/October Pink snapdragon type flowers
Cimicifuga racemosa Bugbane Part shade to sun Moist 5’-6’ July/September Bold woodland edge plant with white, wand-like blooms; handsome foliage
Coreopsis verticillata Tickseed Sun Dry to moist 2’-3’ June/July Yellow mini-daisies are held above delicate mound of lacey foliage; slowly spreading to form a small colony
Dennstaedtia punctilobula Hay scented fern Sun to part shade Dry to moist 1’-3’ n/a Spreads rapidly; fragrant, light-green foliage turns yellow in fall
Echinacea purpurea Coneflower Sun Moist to dry 3’ July/August Pink petals surround a bronze cone; a butterfly magnet
Eupatorium maculatum Joe Pye weed Sun Wet to dry 5’-8’ July/August Huge, dusty-pink flowers attract butterflies; good fall color
Eupatorium rugosum White Snakeroot Part shade to sun Wet to moist 3’-4’ September Long lasting, fuzzy white flower clusters; cv. Chocolate has purple/brown foliage
Filipendula rubra Queen of the prairie Sun Moist 4’-6’ June/July Prefers well-drained evenly moist soils but will tolerate wet soils; foamy clusters of tiny pink blooms.
Geranium spp. Perennial geranium Sun to part shade Moist to dry 10”-18” May/July Many species and cultivars; colors range from white to pink to blue
Hemerocallis spp. Daylily Sun to part shade Moist to dry 2’-3’ Summer Many colors; extend season with early, mid, and late blooming cultivars; drought tolerant
Heuchera spp. Coral bells Part shade to sun Moist 1’-1.5’ May/June Pink, coral or white flowers on spikes, many cultivars with purple/silver mottled foliage
Hibiscus moscheutos Rose mallow Sun Wet to moist 3’-5’ July/September Shrub-like plant; very large pink or white flowers; hummingbird nectar plant; can grow with roots in water
Hosta spp. Hosta Part shade to sun Moist to dry 6”-3’ Summer Hosta come in many sizes and foliage colors; mostly grown for foliage, their flowers are quite attractive; remarkably drought tolerant once established
Iris siberica Siberian iris Sun Moist to dry 3’-4’ May/June Many colors, foliage turns apricot yellow in fall
Iris versicolor Blue flag Sun Wet to moist 2’-3’ May/June Deep blue blooms on attractive grass-like foliage; can grow with roots in water
Liatris spp. Gayfeather Sun Dry to moist 2’-4’ July/August Tall stems carry purple flowers that open from the top down; foliage is grass-like; very drought tolerant
Lobelia cardinalis Cardinal flower Part shade Wet to moist 3’ August Will grow in full sun if kept moist; brilliant scarlet flowers attract hummingbirds
Lobelia siphilitica Great blue lobelia Part shade Moist 2’-3’ August/September Blue flowers remain in bloom for 3 to 4 weeks
Matteuccia pennsylvanica Ostrich fern Sun to shade Moist 4’-5’ n/a Plants form colonies by underground rhizomes; tall, gracefully arching fronds
Monarda didyma Beebalm Sun to part shade Moist 3’-4’ July/August Many cultivars available in a range of colors and mildew resistance; forms small colonies; attracts hummingbirds and butterflies
Osmunda cinnamomea Cinnamon fern Shade to sun Moist 3’-5’ n/a Interesting cinnamon colored spore fronds appear in the center of the plant; needs constant moisture if in sun
Panicum virgatum Switch grass Sun Dry to moist 3’-6’ July/September Many good cultivars available; tolerates flooding; airy seed heads in summer
Rudbeckia spp. Black eye Susan Sun Dry to moist 2’-5’ June/September Many different species offer color through the season; both annual and perennial
Schizachyrium scoparium Little Bluestem Sun Dry to moist 3’-4’ August Lovely native grass, blooms in August and turns buff/golden in fall; dense root system; tolerant of poor soils
Solidago spp. Goldenrod Sun Dry to moist 18” – 4’ July/October Many species available; does not cause hay fever; great late season color
Tiarella cordifolia Foam flower Part shade to sun Moist 1’ May Spikes of foamy white flowers in spring; forms a small colony
Groundcovers
Ceratostigma plumbaginoides Leadwort Sun to shade Moist to dry < 1’ August/September Shrubby groundcover spreads rapidly in loose soil; drought tolerant; brilliant blue flowers; leaves red in fall and spring
Chrysogonum virginianum Green and Gold Partial shade Moist to dry < 1’ May/June Golden daisy-like flowers continue sporadically until frost; spreads easily
Epimedium grandiflorum Bishop's Hat Partial shade to shade Moist to dry 1’ May/June Foliage remains green most of the year, once established it will tolerate dry conditions
Phlox subulata Moss Phlox Sun to part shade Moist to dry < 1’ April/May Evergreen; flower colors range from blue to pink and white; forms mats

Maintaining the rain garden

Just like any other garden, your rain garden will need some basic maintenance to keep it healthy and functioning.

  • Mulch annually to suppress weeds and to keep soils moist, which allows for easy infiltration of stormwater; un-mulched surfaces may develop into a hardpan, which impedes water infiltration. Before applying new mulch, remove the old mulch. Alternately, loosen up the old mulch with a rake and just top dress it with new mulch. The depth of the mulch should never exceed 3”.
  • Weed your garden, especially during plant establishment; newly planted species may have a tough time competing with weeds. Once plants become established, less weeding will be required.
  • The plants in your rain garden will need to be watered regularly during establishment to ensure healthy growth. Once established, plants should be watered in long periods of drought. Water deeply once or twice a week; avoid frequent shallow watering.
  • Keep your garden healthy and clean. Rain gardens should be periodically cleared of dead vegetation and any debris that may collect. Replanting may be necessary over time. If a plant is not doing so well in one location of the garden, it may have to be moved to a wetter or dryer area.

Enjoy your rain garden and your contribution to water quality in your neighborhood.

Written by: Roberta Clark
Revised: 08/2011

Adapted from:

  • How Does Your Garden Grow: A Reference Guide to Enhancing Your Rain Garden.
    LID Manual, Prince Georges County, MD, Dept. of Environmental Resources
     
  • Rain Gardens: A Household Way to Improve Water Quality in Your Community.
    University of Wisconsin Extension and Wisconsin Department of Natural Resources
     
  • Rain Gardens: A How-to Manual for Homeowners.
    University of Wisconsin Extension and Wisconsin Department of Natural Resources
     
  • Backyard Rain Gardens.
    North Carolina Cooperative Extension