How To Create A Rain Garden

Ahhh. Hear the pitter-patter of little raindrops on the roof and window panes. What a relief. But sometimes it becomes a torrent and puddles around the door. Eventually it flows down the street. Maybe not so good.

Much of the runoff doesn’t stay where it belongs – in the soil. It can damage your home by collecting around the foundation, undermining it, or flooding the basement. It can create a problem for the environment by washing pollutants into nearby lakes, rivers and watersheds. The rapid flow of water can contribute to flooding downhill. Perhaps it’s time to act. A rain garden might be your best solution.

What, exactly, is a rain garden?

A rain garden is a good-sized depression in the soil that’s created on sloping ground to catch the water as it flows and hold it, allowing it to soak into the soil.  It’s planted with different plant species – often native – that thrive in the various conditions created by the garden. The plants hold soil in place and  preventing erosion. Their roots absorb water, as well. Pollutants may be neutralized or dissipated.

What size and shape is a rain garden?

The size of your rain garden depends on your landscape and what it will accommodate. It should cover at least 100 sq. feet – best if it’s larger. But if there’s not enough room for that, a smaller one will do; it’s better than nothing.

The depth also depends upon your conditions. It shouldn’t be deep enough to form a perpetual pond, but not so shallow that water flows in and out in a flash – flood, that is. About 4 inches to 10 inches deep should be about right.

Abrupt angles are difficult to maintain, and not particularly appealing. A simple kidney-shape or something similar with gentle curves is desirable and popular.

Where should I create my rain garden?

The best place to create your rain garden is in the path of the downward water flow. You can learn this by observation. There are other situations to consider, too, like foot traffic. It’s best to avoid places where someone might step into it, trip and fall.

Make sure you don’t site it where you’ll encounter utilities, underground cables, or a septic drain field as you dig. More about that next.

How do I create my rain garden?

Call 811 – the national call-before-you-dig phone number. As their website states, “Anyone who plans to dig should call 811 or go to their state 811 center's website before digging to request that the approximate location of buried utilities be marked with paint or flags so that you don't unintentionally dig into an underground utility line.” Then wait for their people to show up. Be patient. Even when the lines are supposedly marked, dig with caution. Cable television lines, especially, are notoriously shallow.

Mark the chosen site in the desired shape. Lay out a flexible garden hose around the garden’s perimeter. It’s temporary, and can be moved about until you’re satisfied with the shape. You may also mark the area with flags or orange spray paint.

Cut the grass short, then remove the sod inside the perimeter with a spade. Better still, rent a sod-cutting machine. Recycle the sod to cover bare spots elsewhere in your lawn.

Dig to the desired depth with gently sloping sides. The deepest level should be near the lower end with a flat base about 24 inches or more across. This will provide a place for some plants to grow, and allow water to percolate downward evenly.

Test the soil pH. You can obtain a soil sample bag from your nearest Cooperative Extension Service office. Follow instructions. Return the sample to the office, and pay a nominal fee. You should receive the results in a couple of weeks.

Amend the site, if necessary. You might need to adjust the pH according to the soil test recommendations.

Test the water absorption rate. Add a few measured inches of water to the site. If the soil is packed hard so that water doesn’t infiltrate quickly – about ½ inch per hour – you’ll need to break through the hardpan using a method called “double-digging.” You might need to add sand, milled sphagnum or compost – mixing well – to enhance the “structure” making it suitable for plant growth, and to improve the “permeability” of your native soil.

Divide your rain garden into zones, and select plants appropriate to each. Depending on the size of the garden, you might choose plants ranging in size from low ground covers to perennials, small or even large shrubs.

    • Zone 1 is the deepest where water will stand the longest. Plants for this area should be able to thrive in standing water for awhile.
    • Zone 2 is an intermediate area where water will stand for short periods, but drain away. It is just above and wraps around Zone 1. Plants for this area should be able to grow in wet or dry ground.
    • Zone 3 is the uppermost, wrapping around the other two, and will be the driest. Plants for this area should be able to withstand periods of dry weather.

Install your plants according to best practices appropriate to each species. Helpful information should be available on plant labels, from garden center staff, books, magazine and online sources such as our GoGardenNow plant catalog, and here at GoGardenNow – The Gardening Blog.

Mulch will not be necessary. Rainwater will be flowing down into the rain garden, and will wash the mulch right along with it making quite a mess. Lawn grass or ground cover perennials should stabilize the slopes around the edges quite well.

Maintain your garden during the early stages with adequate irrigation. This will help your plants to become established and get a good start. Fertilizer may not be needed, especially if compost was incorporated into the soil during site preparation.

Final thought

Enjoy your rain garden knowing that it will help prevent water runoff damage to your home, landscape and even distant watersheds. In addition, it will add interest and value to your property. 

Landscaping With Native Plants On Spring Island

Coastal South Carolina is dotted with secluded island hammocks.  Many of them are pristine, or appear so.  Spring Island, near Beaufort and Hilton Head, is one.  The history of Spring Island is a fascinating tale of Indians, traders, antebellum life, Northern magnates and modern development, not unlike most of the Low-country.  But Spring Island is unique.  Carefully developed to preserve its natural beauty and seclusion, it's easy for the visitor to believe that nothing much has changed since the 1920s.

We arranged to meet with Thomas Angell of Verdant Enterprises, LLC. for a morning tour of a few of his projects on the island.  Thomas specializes in native plants, creative storm water management and imaginative landscape detailing with custom hardscape construction.

As we traveled down picturesque allees lined with magnificent live oaks, we were practically unaware of nearby residences screened from view by dense native plant growth.  Discrete address plaques barely hinted at what was hidden and growing behind those verdant garden walls.

Our first stop was at the residence of one of the area's leading proponents and experts of natural landscaping.  Unfortunately, she was away and unable to meet with us.  Thomas explained that her home was carefully sited to preserve the magnificent trees on the property, as well as to afford a splendid view of the river and marsh.  The structures do not appear to be imposed on the river bank, but to grow in harmony from it, surrounded by such local beauties as wax myrtle (Myrica cyrifera) and needle palm (Rhapidophyllum hystrix).

Both back and front of the home were beautifully landscaped exclusively with native species.  (You should know that the front of every waterfront home faces the water.  Arrival by land is through the back door. Whether through the front or back door, scrape your boots or shed them.)

An ancient oak provided shelter to blood-root (Sanguinaria canadensis), wild ginger (Asarum virginicum), trillium (T. maculatum), jack-in-the-pulpit (Arisaema triphyllum), indian pink (Spigelia marilandica), partridge berry (Mitchella repens), along with colonies of native grasses and ferns.

I was surprised to see the blood-root, wild ginger, trillium, jack-in-the-pulpit, and indian pink, but Thomas informed me that they are actually native to the area.  Botanist and nurseryman, Daniel Payne, owner of NatureScapes Of Beaufort, confirmed it.  Daniel arrived on site unexpectedly to inspect and maintain some of the plantings.  As we walked about, Daniel explained that Beaufort County is one of the most biologically diverse counties in South Carolina, and perhaps in the Southeast, with over 1597 naturally occurring native plant species inventoried to date.

The natural design was "civilized" with some of Thomas's hardscape detailing.  A local soft stone called hardpan was quarried for benches of serpentine or semi-circular patterns.  Because of its porosity, the hardpan was topped with laminated wood seating created by a regional craftsman.

As we toured the site, I commented on a native plant that, so far as I know, is never used elsewhere.  The common names are Devil's Grandmother or Elephant's Foot (Elephantopus tomentosus).  But Thomas had used it quite effectively.  The foliage is attractive, the flowers are charming, and, of course, it grows like a weed.  We agreed that sustainable landscaping using native materials requires that we try to see things through new eyes.  It's really not that difficult or new to see things afresh; all non-native ornamentals were originally weeds from elsewhere.

The owner, Thomas and Daniel had established a display garden nearby with various other native species, and a few regional "heirloom" plants on trial.  A "midden" constructed for the garden rose above a dry stream bed designed to collect and direct storm water to a bog garden.  A pool with flowing water provided habitat for native fresh-water aquatic plants, and also created a refreshing oasis of sight and sound.

Native landscaping involves philosophical discussion.  For example, one might wonder whether or when a native plant should be considered desirable.  Such is the case in this garden with poison ivy.  The typical reaction to poison ivy (Toxicodendron radicans) is to eradicate it.  But Daniel noted one specimen on the river bank which he allowed to remain.  The foliage, he explained, is quite colorful and attractive in the fall while the towering plant provides habitat and the seeds provide food for wildlife.  It grows at some distance from foot paths.  But then, the birds drop the seeds about the landscape to propagate more.  There comes a point when enough is enough and the solution calls for a squirt of herbicide.

Thomas was curious to take a look at some other projects he had completed several years ago.  A quick look now would prepare him for upcoming appointments with the owners.  It was disappointing to see that the plantings had not been properly maintained.  In my opinion, they demonstrated a lack of sensitivity on the part of some maintenance crews, or perhaps a lack of knowledge which can be remedied.  Expanses of lovely native grasses had been mowed like sod.  Soft cushions of billowing shrubs had been flattened at breast height like table tops.  Certainly, landscaping with native plants in naturalistic settings presents a new paradigm that must be studied carefully in order to maintain and appreciate.

Considering these examples of sustainable landscaping, one might assume that a naturalistic planting of native plants is by definition no-maintenance or low-maintenance.  That is not always true.  The level of maintenance depends, as with other types of landscaping, upon the form, function and appropriateness of the whole and its parts.  A building or structure may appear to be unified with the natural surroundings, but it is not actually, and nature is always on the move.  Sooner or later, considerable maintenance is in order.  Nevertheless, landscaping with native plants is a refreshing new concept which time has come.

The following is a partial plant list of species we noted.

Aesculus pavia var. pavia
Amelanchior x Autumn Brilliance
Ampelaster caroliniana
Arisaema triphyllum
Asarum virginicum
Campsis radicans
Carex grayi
Chasmanthium laxum
Clematis catesbyana
Cocculus carolinus
Conoclinium coelestinum
Cornus asperifolia
Dichromena colorata
Elephantopus tomentusus
Erythrina herbacea
Eupatorium purpureum
Eustachys petraea
Fothergilla 'Mt. Airy'
Gelsemium sempervirens
Helianthus hirsutus
Heliotropium curassavicum
Heterotheca graminifolia
Hypericum hypericoides
Ipomoea macrorhiza
Juniperus virginiana 'Brodie'
Krigia dandelion
Lobelia cardinalis
Lyonia lucida
Mitchella repens
Monarda punctata
Myrica cerifera
Nymphea spp.
Passiflora lutea
Quercus virginiana
Rhapidophyllum hystrix
Salvia lyrata
Sanguinaria canadensis
Scuttelaria integrifolia
Serenoa repens
Spigelia marilandica
Stipa spartea
Symphotrichum concolor
Rudbeckia maxima
Ruellia carolinensis
Trillium maculatum
Tripsacum dactyloides
Toxicodendron radicans
Verbena rigida
Viburnum acerifolium
Viburnum obovatum
Vitis rotundifolia
Yucca recurvifolia

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Conserve Water With A Rain Garden

Water conservation has been on almost everyone's mind for many years. When I was a kid, my parents would remind me to "turn off the faucet all the way! Money doesn't grow on trees!" A more recent concern is that water may run off to where it isn't so easily accessible.

In an effort to help rain water soak into the ground instead of flowing from pavement to the sea, many municipalities require that new commercial developments construct "retention ponds." Intentions may be good, but those things are expensive, dangerous and ugly. Located on high-priced real estate and usually surrounded by chain link fences for safety/liability reasons, they look like marshy dumps filled with plastic bags, styrofoam cups, disposable diapers and whatever else is washed downhill.

How much better it would be for homeowners to take matters into their own hands and construct rain gardens. Rain gardens are nothing more than shallow depressions in the yard located near driveways or roofs to collect water runoff. Planted with moisture-loving plants, they become attractive features in the landscape that serve a good environmental purpose. They can even attract wildlife. Rain gardens are low-maintenance, too.

Here is how to go about it; you can begin any time of year. Choose a site where water would naturally shed: a bit downhill from a downspout or roof, air conditioning unit, driveway or walk. You may direct water in the right direction with drain tubing or a very shallow swale. In my opinion, rain gardens near homes should be 15 feet or more away from the foundation. Exposure to full sun is desirable, but not necessary.

Plan the size of the rain garden by drawing the contour of the area with marking paint. If you need to make changes, you can edit your work by erasing the marks with your foot when the paint has dried.

Size is not very important. Adapt it to the space available. Approximately 25 square feet is okay; 100 square feet is fine; larger is better.

When you are satisfied with the contour, remove the sod and construct a shallow depression. The sides should slope gradually. You may add a few inches of soil as a low berm around the edge of the down-hill side to prevent water from escaping.

Keep in mind that you aren't constructing a pond, so it need not be very deep; 6 inches to 8 inches deep is sufficient. You don't need to install a liner, either. The garden need not be constantly wet; the idea is for rain water to soak into the soil, not to stand indefinitely. If, however, you wish to form a bog garden, you can do that by digging the depression a bit deeper.

Choose plants that like moist soil. Native grasses, sedges, perennials and small woody shrubs are ideal. Many native plants are recognized for their ornamental value. Sometimes they even establish themselves naturally! But non-native plants are good, too. Whether to weed or not is your choice.

An added advantage of a rain garden is that it doesn't require mowing. HooRAY!!! That much less to do. Just mow around it and go on.

Maintenance is minimal. Trimming brown stalks in early spring will keep your garden tidy and allow new growth to sprout unhindered.

If you would like to see what a rain garden looks like before you begin construction, check with nearby nurseries, botanical gardens and nature centers. Since rain gardens are becoming quite popular lately, you shouldn't have far to travel. For more precise information, resources are available on the internet.

Your new rain garden will enable you to conserve water, enhance your gardening experience, beautify your home, provide habitat for wildlife, and maybe even reduce the time you spend maintaining your landscape. It's a great solution.

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Planning And Planting To Conserve Water

Whether you garden in a dry region or one with typically adequate rainfall, it is always a good idea to think about water conservation and to plan your landscape accordingly. Three steps should top your list:

1. Have your soil tested. Soil tests can reveal a lot that you may not know. Your local garden center or nearby Cooperative Extension Service can help you. By suggesting how you may improve your soil, nutrient uptake by plants may be enhanced and water conserved.

2. Locate your water source. Will you be relying on a community water supply or your own well for irrigation? There may be ways to obtain water in other ways. Rain barrels can help you harvest and store water coming off your roof. Rain gardens catch run-off and prevent its loss. It might even be possible to take advantage of water dripping from your air conditioning unit! No, I am not kidding.

3. Put "the right plant in the right place." Walk around your landscape and map areas that are wet, dry, shady and sunny. Take note of sun exposure during different times of day. Typically, high areas or spots in your landscape will be dry; low-lying areas will tend to be moist. Select plants that have requirements appropriate to those sites. By planting sun-loving, drought-tolerant plants together, and by planting moisture-loving plants in wet areas you will avoid watering unnecessarily or under-watering.

Be creative! Think of all the ways you can save water, time, money and energy.

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