Wetland

Wetlands filter excess pesticides

and nutrients. Many plants and

animals find a home in wetlands.

In your backyard

A mini-wetland in your yard can provide many of the same benefits that

natural wetlands offer. A mini-wetland can replace the important natural functions of wetlands that may

have been lost when your community was developed.

A wetland in your backyard will

temporarily store, filter, and clean

runoff water from your roof and

lawn. It will provide habitat for many

interesting creatures--from butterflies

and bees to salamanders, toads, frogs,

and birds.

Most wetland plants do not require

standing water to grow successfully,

and will survive even in an area that

appears dry during most of the

growing season.

If you have a naturally occurring wet

spot in your yard, or a low swale or

drainageway with heavy clay soils,

you easily can turn it into a wetland

paradise. Even if you do not have a

naturally wet spot, you can establish

an area in your yard to grow many of

the beautiful plants associated with

wetlands.

What is a wetland?

A wetland is simply any area where

water covers the soil or keeps it

saturated for at least two or three

weeks during the growing season.

You will usually find them anywhere

is a cooperative project of:

USDA Natural Resources

Conservation Service

National Association of

Conservation Districts

Wildlife Habitat Council

April 1998

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One in a series of 10 tip sheets on backyard conservation

Backyard

Conservation

Even if you do not have a naturally wet

spot, you can establish an area in your

yard to grow many of the beautiful

plants associated with wetlands.
water accumulates at a rate faster

than it drains away. Some are inundated year-round while others only

hold water for brief periods in the

spring. Most wetlands are covered

with water for less than a month

during the summer.Wetlands dominated by grasses, cattails, and similar

herbaceous vegetation are referred

to as marshes, while wooded wetlands, dominated by shrubs and

trees, are called swamps.

The saturation of the soil limits the

types of plants you can grow to

those with “wet feet.” How long the

soil is saturated determines which

wetland plants will grow best.There

are many small wetland plants that

grow quickly when the soil is wet in

the spring and disappear when the

soil dries up. Species like cattails,

bulrushes, jewelweed, and the attractive cardinal flower do well where

there are alternating wet and dry

periods.These plants will survive

persistent flooding as long as most

of the leaves are out of the water.

Water lilies and pond weeds grow

well in permanently flooded ponds.

In your backyard, toads and tree

frogs (spring peepers) will lay eggs

and the pollywogs will mature

where water only lasts 3 or 4 weeks;

other frogs need longer periods.

Where you have permanent water,

the bullfrog pollywogs and small fish

limit survival of most other frogs,

toads, and salamanders. Mosquitoes

will not survive in wetlands that dry

out in less than a week after a summer rain or in wetlands connected

to a deeper pond that supports small

fish and large aquatic insects that

feast on them.

Where to put a

wetland

A natural depression or ditch that

tends to stay wet is an ideal

place to develop a wetland. Other

areas with heavy clay soils that

drain slowly may also be suitable.

Better drained sites may require use

of a plastic or other type of liner. Of

course, if you are building a backyard pond, as discussed in another

tip sheet in this series, a shallow area

of saturated soil can be incorporated

in the design.When selecting a site,

consider:

• Is the site away from your foundation, out buildings, existing landscaping that you want to maintain, or neighboring properties

that might be damaged by excessive moisture?

• Would there be a safety concern

for neighborhood children?

• How will the site be integrated

into your plan for maintenance?

• If you need supplemental water, is

it readily available or can you use

roof drainage?

• If there is an existing wetland,

check wetland regulations before

altering it.

• Unless you completely own a

ditch, check with local authorities before making any alterations. Be sure you won’t cause

adjacent properties to flood.

Safety

Locate the backyard wetland where

it is unlikely to attract unattended

children. Check local safety ordinances to determine if a fence is

required for the specific depth and

size of your wetland. Check local

building ordinances for depth and

safety restrictions and permits.

Building a wetland

Since wetlands refer to a variety of

conditions, there is a lot of potential

for including wetland plants in your

yard.You may want a wetland that

only stays wet for a short period

after heavy rains or one that stays

wet most of the time. It depends on

the site and your desires. Establishing

a wetland in your yard may be as

simple as planting wetland plants in

an existing wet area, or it may

require the same effort needed to

install a backyard pond.

Building a wetland

in an existing wet

area or drainageway

If the area is naturally wet during

parts of the year, no mowing during

the dry season may be all that is

needed to allow naturally occurring

wetland species to proliferate.Too

often homeowners go to great

lengths to establish plants that are

not adapted to the site or to modify

the site, when it would be more

effective to use plants suited to the

conditions. Numerous landscape

plants are well adapted to wet conditions and will provide beauty as well

as wildlife habitat.

Be sure to check the growth and

rooting characteristics of trees you

want to plant. Many wet soil tolerant

trees have shallow root systems or

brittle branches and must be planted

a safe distance from buildings.

Partially blocking a drainageway or

small ditch to create your wetland

by trapping storm water needs more

planning.Where a low berm less

than a foot high will create a small

wetland, planning is not complicated

if:

• the drainage area above the berm

is small, generally less than an

acre;

• there is adequate area for flood

flows to go around and over the

berm; and 

• the soil contains a high percentage of clay.

For sites requiring a higher berm,

and those with a larger watershed,

you need engineering advice. For

sites with sandy soil or a lot of rocks,

you may also need to install a plastic

liner (described in the next section)

under all or the lower portion of

your wetland.

BACKYARD Wetland

2
To construct the wetland with a

small berm to hold back water for a

few days or weeks:

1. Put a stake in the center of the

lowest portion of the drainageway

where you want the berm.

2. Using a level on a large board or

string, place a stake where a level

line reaches the ground on either

side.

3. Using the same type of level, mark

how far back water will be impounded at the top of the berm.

4. Remove any existing sod from an

area about 4 feet wide along the line

of the berm and over about half the

area that will be flooded.

5. Dig a trench about 1 foot deep

along the center line of the berm

and fill it with slightly damp heavy

soil, packed down firmly.

6. Build your berm about 4 feet wide

at the bottom and 1 foot at the top.

The center should be 4 to 6 inches

higher than the ends to allow for settling and to force water flowing over

it around the ends, reducing the likelihood of erosion.

7. Cover the compacted berm with

purchased grass sod or the sod you

originally removed from the area.

8. Plant wetland adapted plants in

bands from the deepest areas to an

area about six inches above the

expected high water level, selected

according to the degree of soil saturation they require.

Building a separate wetland

You can create a wetland in any level

area and make it suitable for most

wetland plants by digging out a

depression, lining it with plastic,

refilling it with soil, and adding

water. After selecting the site, you

should:

1. Using a hose or rope, lay out the

shape of your wetland. An irregular

shape will appear the most natural.

Sometimes a long narrow curving

wetland will fit nicely into a landscape plan.

2. Excavate an area 1-1/2 to 2 feet

deep.The sides should slope gently

to the deepest area.

3. Put an inch of fine sand or loose

soil in the bottom to prevent the

plastic liner from being punctured

by small stones.

4. Line the depression with sheet

plastic. Hold in place with heavy

objects such as round stones. Or,

install a pre-formed pool liner or use

a child’s wading pool.

5. If you live in a region with heavy

annual rainfall, puncture the liner in

several places with pencil-sized

holes about halfway up the sides to

allow slow drainage so the soil will

not stay completely waterlogged for

long periods.

6. If you plan to grow common

species of low maintenance plants

adapted to moist soils in your area,

fill the depression with a mixture of

soil and peat. A significant amount

of peat will help retain moisture and

allow for aeration.

If you intend to grow true bog plants

that require acidic soils saturated

with water most of the year, fill the

area with a mixture of half peatmoss

and half humus.Also, you should fill

the lower half of the depression

with pea gravel or coarse sand to

assure more even distribution of

water. Burying a perforated pipe in

the pea gravel connected to an

upright pipe fitted with a hose connection will help add water evenly

to the bog.

7. Cover the edges of the plastic

with soil to hide them and hold the

liner in place.

BACKYARD Wetland

3

You can turn a low swale in

your backyard into a wetland.
BACKYARD Wetland

4

Building a wetland

by a backyard

pond

Putting a shallow wetland at one

edge of your backyard pond will

increase its value and attractiveness.

If you are using a pre-formed liner

for your pond, you may want to

build the wetland as described

above, with the water level slightly

above the pond liner or the edge of

the pond liner lowered a couple of

inches to allow water to flow into

the pond.This design filters sediment and other contaminants out of

the water coming off your lawn or

roof through the wetland before it

enters the pond.The wetland area

also protects fish and other aquatic

life in the pond by removing any

chlorine from city tap water you use.

Establishing plants

The plants you select for your wetland will depend on:

• length of time the soil will be saturated or covered with water,

• depth of the water,

• amount of sunlight on the site,

• climate,

• soil pH, and

• size of the wetland.

Select plants that are hardy for your

area and provide the desired wildlife

habitat and aesthetics.The species of

plants most common in other wetlands in your area with similar flooding cycles will be easiest to grow

and need the least maintenance.

Choosing and

establishing plants

for ponds

To make part of your backyard like

natural wetlands, use a mix of

diverse plants. Most trees, shrubs,

ferns, and many other plants grow

best in soils that are only saturated

early in the growing season and after

heavy rains. Others, like the true bog

plants, need almost continually saturated soil. Plants like water lilies

need to be continually flooded. Once

established, plants like cattails will

thrive in water a couple feet deep,

but also in areas that are wet for

only short periods. However, most

have a narrower tolerance range live.

Always check with your local nursery or other expert before making

final decisions on what varieties to

plant. Plants should always be purchased from a reliable source.

Native trees tolerant of wet soils:

Red and silver maple (Acer rubrum,A.

saccarinum)

River birch (Betula nigra)

Catalpa spp.

Ash (Fraxinus spp.)

Cottonwood (Populus deltoides)

Swamp white oak (Quercus bicolor)

Sycamores (Platanus spp.)

Native shrubs tolerant of wet soils:

Red osier dogwood (Cornus sericea)

Leatherwood (Dirca palustris)

Winterberry (Ilex verticillata)

Inkberry (Ilex glabra)

Pussy willow (Salix discolor)

Shrubby cinquefoil (Potentilla fruticosa)

Native herbaceous and flowering

plants for sunny moist or boggy

conditions:

Cattails (Typhus spp.)

Joe-Pye weed (Eupatorium maculatum)

Great blue lobelia (Lobelia siphilitica)

Ironweed (Vernonia noveboracensis)

Blue flag iris (Iris versicolor)

Boneset (Eupatorium perfoliatum)

Cardinal flower (Lobelia cardinalis)

Goldenrods (Solidago spp.)

Marsh marigold (Caltha palustris)

Swamp milkweed (Asclepias incarnata)

Gentian spp.

Native herbaceous and flowering

plants for shady moist or boggy

conditions:

Bee balm (Monarda didyma)

Arrowhead (Sagittaris latifolia)

False hellebore (Veratrum viride)

Turtlehead (Chelone spp.)

Royal fern (Osmunda regalis)

Skunk cabbage (Symplocarpus

foetidus)

Netted chain fern (Woodwardia areolata)

Jack-in-the-Pulpit (Arisaema triphyllum)

Cinnamon fern (Osmunda cinnamonmea)

Shield ferns (Dropteris spp.)

Lady ferns (Athyrium spp.)

True bog plants requiring low pH

and sun:

Sundews (Drosera spp.)

Butterworts (Pinguicula spp.)

Pitcher plants (Sarracenia spp.)

Many other native wetland species

are available in most areas.There are

also many species that have been

naturalized in North America and are

often considered native plants.

Unfortunately, some of these species

are more competitive and have

become invasive, crowding out

native species that provide habitat

for indigenous wildlife.

On the farm

In the rural landscape, wetlands filter

chemicals, excess nutrients, and sediment from flowing water, protecting

streams and drinking water sources.

They also provide wildlifehabitat .

Across the country, many farmers

voluntarily return formerly drained

wetlands in crop fields and pasture

to fully functioning wetlands. Many

of these acres were marginally productive; returning them to wetlands

provides significant ecological, economic, and recreational benefits.

Many farmers enhance their wetlands with nesting structures for

ducks and other birds, put in plants

and annual seeding to provide winter food and cover for wildlife, and

establish native wildflowers to make

the landscape more attractive.

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