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Wise Water Usage
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Wise Water Use
Waste not, want not
How to keep the water you get and stop wasting what you use

By George Weigel, Pennsylvania Certified Horticulturist (PCH)

For such a critical gardening ingredient, water doesn't get much respect.

So long as a steady stream comes out when we turn on the hose, many of us take water for granted. And as a result, much is wasted.

One reason is that Pennsylvania historically has been blessed with good rainfall and decent groundwater supplies. We haven't had the serious water shortages that many states routinely face.

So far.

Why wise water use matters

But with water consumption rising and climate change threatening warmer temperatures and even more erratic weather extremes, our seemingly infinite supplies aren't guaranteed.

"Water is a limited resource," reminds Josh Imel, a certified landscape irrigation specialist with The Brickman Group in Exton, Pa. "Using water without conscience is easy because there are no penalties. Water appears to be relatively abundant and inexpensive."

Compared to energy production, industrial use, leaky water lines and the like, water use in the landscape amounts to a trickle in the bigger bucket. Yet especially when drought hits, watering lawns and gardens becomes a key conservation target because it's such a visible use of water. In our climate, water use also peaks in summer from a variety of uses — sometimes rising 40 percent from other times of the year.

Homeowners can help simply by eliminating water-wasting habits outside, such as running sprinklers that spray onto sidewalks, watering plants and lawns that really don't need it, and forgetting about that running hose.

"Running a hose for a few hours while you go shopping is not an effective use of water," says Imel.

But too much water during rains is as important an issue as too little water during droughts. How effective your landscape is in keeping rainwater on site can make a huge collective difference in recharging groundwater, reducing flooding and reducing polluted runoff.

Why? Because the more we replace fields and forests with houses, concrete sidewalks and asphalt streets, the more water runs off into storm sewers and streams during rains. Instead of soaking in and recharging local groundwater, rain runs off and contributes to flooding. When lawn and garden chemicals ride along with the runoff, that also increases pollution problems downstream.


Pollution can be reduced by using less fertilizer, fewer pesticides and/or by switching to more natural products, says Jim MacKenzie, president of the Lancaster County–based Octoraro Native Plant Nursery and former vice chair of Pennsylvania's Statewide Water Resources Committee, which updated the state's water plan in 2008 — the first update in 30 years. (For more on reducing chemical use in the landscape, read about earth-friendly design and organic lawn care.)

"Many people think that more is better, and so they over-apply fertilizers and chemicals," MacKenzie says, adding that many plants do just fine with even half the fertilizer recommended by product labels.

For those living near waterways, he suggests streamside plantings instead of lawns right up to the banks. "Plantings provide aesthetics to the stream while protecting the banks from erosion and runoff," MacKenzie says.

Any homeowner can use that same principle by replacing lawns with island or border gardens. Lawns growing on poor, compacted soil and mown short (as so many homeowners do) can produce runoff that's not a whole lot better than asphalt driveways. Gardens absorb water better because they're usually mulched, and the soil is loosened and improved.

"Plantings help intercept rainwater before it leaves the property," says Rebecca Wertime, project coordinator for the Pennsylvania office of the Alliance for the Chesapeake Bay.

Rain gardens
A new trend that takes that idea a step further is a rain garden.

"These are shallow depressions that collect runoff from rooftops or paved surfaces," says Wertime. "It captures and slows the runoff and allows it to drain down into the ground. It also captures pollutants and filters them naturally in the soil. The old way was just to get water off the property as soon as you can."

The most common approach is to direct runoff through a stone-lined channel into the rain garden, which has been dug and improved with well draining soil. An ideal mix is about 20 percent compost, 50 percent sand or sandy soil and 30 percent native topsoil. The bed is built in a depression that's about 4 to 6 inches below grade — enough to catch and drain runoff within 4 to 6 hours but not as deep as a retention basin.

Rain gardens are ideally sized about as big as the area being drained. They're planted with species that tolerate periods of wet soil. (More information on rain gardens is available at An excellent downloadable booklet from the University of Wisconsin Extension Service called, "Rain Gardens: A How-to Manual for Homeowners" is available at

Green roofs

Even newer is the concept of a green roof, which is catching on recently in Europe. Instead of shingles, these roofs have rubber liners topped with several inches of light soil planted with low-maintenance groundcovers such as creeping sedum, thyme and hardy ice plants.

"Green roofs are starting to make serious advances in this country from corporate down to individuals," says MacKenzie. "These roof systems help absorb a percentage of the stormwater before it ever leaves the roof surface."

Planted roofs also cool homes and reduce air-conditioning costs in summer. (For more on these, go to the Green Roof Industry Association at, Penn State University's Center for Green Roof Research at, or Maryland's Emory Knoll Farms, which specializes in green-roof plants, at

Better water absorption
Simply aerating lawns to reduce compacted soil also can help once water hits the ground. Going with water-absorbing surfaces such as mulch or brick paths and paver-block patios instead of solid concrete and asphalt is another way to reduce runoff. And using rain barrels at one or more spouts is a great way to collect runoff for later recycled use in the garden.

One of the best things you can do is just pay attention to what's happening to water on your property in the first place, says Dr. Jim Sellmer, assistant professor of horticulture at Penn State University. Unless the basement is being flooded or a gully is being worn in the front lawn, water movement is usually ignored.

"Observation will tell you where you have problem spots," Sellmer says. "When is water present? Where is water going? What do you have planted and how is it doing? You can choose plants that do well in wet areas and help reduce water drainage issues to some degree depending on what you plant where."

If you're getting erosion or soggy spots long after rain is gone, you may need drainage tiles, buried pipes or swales to either carry the excess away or help it dissipate over a wider area, says Sellmer. If it's more periodic and temporary pooling, planting wet-soil plants or adding a garden in place of a compacted lawn may be the answer.

Get the most out of your water
At the other end of the spectrum is taking steps to use water more efficiently in the landscape.

An obvious place to start is knocking off blatantly wasteful practices.

At the top of MacKenzie's list: "Excessive watering of lawns and plants by methods that are easily forgotten, such as hoses and sprinklers with no automatic shutoffs. People turn these on and go do something else and forget the water is running." Once the ground becomes saturated, water runs off.

A close second is positioning sprinklers so that water sprays directly onto driveways and sidewalks. That also wastes water from drop one.

Lawns — to water, or not to water

A little trickier is determining which plants need water, when, and how much to deliver so water isn't over-applied. The main potential water-user in most landscapes is the lawn. MacKenzie says lawns are adaptable enough that they need water only in the worst of droughts, and even then, only enough to keep the crowns alive until rain ultimately greens up the blades.

"In times of drought, your lawn simply goes dormant and does not need to be watered at a time when other societal needs and pressures need to take priority over lawns," he says.

For those who must have a green lawn all season every season, Imel advises watching for early signs of drought stress instead of automatically watering by the calendar.

When to water
"Look for signs such as when walking across the grass, the blades stay down and you can see your footprints long after you've walked through," Imel says. "The color of the grass also begins to look bluish or even gray compared to the normal deep green. And as the soil becomes dry, it pulls away from hard surfaces such as a walkway."

In general, it's much better to water a lawn deeply once a week than to apply light sprinklings every day or two. Applying about 1 inch of water over the lawn is usually enough to supply the roots with adequate moisture for a week. That can be measured by setting several tuna cans throughout the lawn. When the cans have an inch of water in them, you've run the sprinklers long enough. Shallow watering quickly evaporates and doesn't get water down to the root zone, plus it can encourage thatch and lawn diseases.

The most effective way to water lawns, says Imel, is to have a professional install an automatic sprinkler system. "An automatic system saves so much water that it can pay for itself in water savings after several years," he says.

How to water
How? Professional systems can be set up to water by each zone's needs, and sprinkler heads can be precisely positioned and adjusted so they spray only on the grass. Rain shutoff devices can be added so the system won't operate if rain already has supplied adequate moisture.

"An automatic system puts the water down where it is needed, when it is needed, and how long it is needed," says Imel, adding that the use is typically 50 to 60 percent less water than setting portable sprinklers throughout the yard. "Imagine not having to go outside every night to drag a hose and sprinkler around the yard, only to forget occasionally that you left it running all night."

Whether you're watering a lawn or garden, it's also important to avoid applying water so fast that it runs off. Compacted lawns don't absorb water very fast, and even mulched beds often have to be wet gradually to break the surface tension before water soaks in well.

A good way to ensure that, says Imel, is to use what he calls the "cycle and soak" method.

"Say you have an area of turf that needs 30 minutes of watering, but after 10 minutes you realize the water is running into the street," he says. "This means the water-holding capacity of the soil has been maximized, and watering is now ineffective. Try watering instead in three 10-minute increments spaced 15 to 30 minutes apart."

The same can be done if you're using a hose to water garden plants. Rather than water everything in one fell swoop, make several passes through a bed — watering several times in smaller doses. Automatic systems can be set to cycle on and off several times with "soak breaks" in between rather than running for 30 minutes straight.

Then there's the issue of determining how often you really need to water in the first place. Some plants require more water than others, so if you choose plants that are naturally drought-tolerant, you'll be able to cut your watering drastically.

If you want to grow water-hungrier plants, they can be grouped in a naturally damp part of the yard. If you don't have a damp spot, grouping them at least focuses watering just to that area instead of having to spot-water them all over the yard or needlessly sprinkling the drought-tough plants along with their water-hungry neighbors.

"Very few in-ground plants need watering every day," says MacKenzie. "Most will be fine with weekly watering when initially planted, and once established after the first 6-12 months, most should not require watering if it's the right plant for the right site."

One of the best gauges for determining when it's time to water: your index finger. Just stick your finger down into a garden bed a few inches to see if it's cool and damp or bone dry. Moisture meters also are available at most garden centers if you'd rather go higher-tech.

Don't just assume that because a plant is wilting, that means it needs water. Sometimes people overwater plants in poorly drained soil, which rots the roots. With dead roots, the top growth isn't getting the moisture it needs and therefore wilts — the exact same look as when there's not enough moisture in the ground! A finger check can quickly separate out the two.

Check your soil
Before planting, here's a way to check how well your soil drains:

Dig a hole similar to the size of the rootball you plan to plant or one that's about a foot around and 18 inches deep. Fill the hole with water and let it drain for 24 hours.

The next day, refill the hole with water and watch to see how fast the level goes down. The level should be going down by at least 1 inch per hour. If it's draining less than one-half of an inch per hour or still has water in the bottom 24 hours later, you have very poor drainage that should be corrected with generous amounts of compost or similar organic matter. Raised beds that will get plant roots up and out of the potentially soggy soil also are an option.

To determine how fast an existing bed is drying out, soak a foot-wide area with a hose for about 2 minutes. Once the water soaks in well, use a trowel to pull back an opening in the soil so you can use your fingers to feel the soil 3 to 4 inches deep.

The soil should be cool and damp at that depth after the soaking. Each day, do the same check without watering to see how many days the soil is still cool and damp. When it becomes warm and dry, that gives you a clue how long the bed can go between waterings under the kind of conditions you've been having.

Be aware that these times will vary depending on weather and the location of the beds. This feedback gives you site-specific information on when it's time to water a particular area.

George's wise water use tips

Some ways to wisely use water in the landscape:

* Reduce evaporation loss from garden beds by maintaining a 2- to 4-inch layer of organic mulch (shredded bark is ideal) on top of all bare soil. Mulch also helps water to soak in.

* It's best to water early in the morning when evaporation loss is low and when increasing light and warmth will dry out leaves to lessen the threat of disease. Also a good time is late afternoon to early evening — times when plants' water needs are highest but still early enough for leaves to dry before nightfall.

* Pay attention to exposure. Plants in sunny and windy areas are going to use more water than those in shaded or protected areas, so water accordingly.

* Consider the weather and season. A plant's water demands go up on hot, sunny days and go down on cloudy, cooler days. Peak demands are in mid-summer, so you'll usually have to water more then than in April or October.

* Consider using recycled "gray water" from the house (i.e. dish water, air-conditioner condensate, water from dehumidifiers, etc.) on ornamental plants.

* Pay special attention to watering on slopes. Water tends to run off quicker, so you may need to apply lesser amounts several times to get the job done without wasted runoff.

* If your yard is small and you're patient, watering by hand with a hose or bucket is best. This allows you to custom-direct water exactly where it's needed. And you can immediately adjust if water begins to run off.

* Soaker hoses and drip-irrigation systems are good do-it-yourself automatic alternatives. Just be sure to use a timer so you don't forget to turn these systems off. And monitor them regularly to be sure hoses aren't kinking and emitters aren't clogging.

* If you use sprinklers, choose types that let you direct the spray as precisely as possible. One example is the "Noodlehead" sprinkler, which has a dozen bendable tubular tips that can each be directed. (

* Consider watering aids such as TreeGator bags, soaker-hose rings and irrigation tubs, especially for new trees and shrubs. These are no-runoff ways to gradually apply water to root zones at selected intervals.

* When digging new beds, work compost or other organic matter into the soil to improve its drainage and water-holding ability.

* Especially in windy areas, consider planting trees, evergreens and taller shrubs that can serve as windbreaks to reduce evaporation losses from flowers, small shrubs and the vegetable garden.

* Reduce water loss from hanging baskets by lining the insides with black plastic (except for the bottom!) and using a small amount of water-absorbing crystals in the potting mix. Crystals also can be used in flower pots.

* When watering a new tree or shrub, direct most of the water close to the trunk during the first season. Initially, you'll usually need to water twice a week (on average, 3 to 5 gallons per watering), cutting back to once a week after the first 6 to 10 weeks unless it's very hot and dry. As the roots reach out, extend water to just beyond the plant's canopy. A good rule of thumb on quantity: 1 gallon of water per square foot of soil being watered.

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Wet-tolerant plants that make good choices for a rain garden (N indicates plants that are native to the mid-Atlantic region)

American fringetree (Chionanthus virginicus)

Black gum (Nyssa sylvatica) (N)

Green ash (Fraxinus pensylvanica) (N)

Honeylocust (Gleditsia triacanthos) (N)

Redbud (Cercis canadensis) (N)

Red maple (Acer rubrum) (N)

River birch (Betula nigra) (N)

Serviceberry (Amelanchier canadensis) (N)

Swamp white oak (Quercus bicolor) (N)

Sweetbay magnolia (Magnolia virginiana) (N)

Sweetgum (Liquidambar styraciflua) (N)

Willow oak (Quercus phellox) (N)

American holly (Ilex opaca) (N)

Baldcypress (Taxodium distichum) (N)

Inkberry holly (Ilex glabra) (N)

Larch (Larix spp.)

White spruce (Picea glauca)

American cranberry viburnum (Viburnum trilobum) (N)

Arrowwood viburnum (Viburnum dentatum) (N)

Bayberry (Myrica pensylvanica) (N)

Black chokeberry (Aronia melanocarpa) (N)

Buttonbush (Cephalanthus occidentalis) (N)

Elderberry (Sambucus canadensis) (N)

Fothergilla (Fothergilla gardenii, major)

Fragrant sumac (Rhus aromatica) (N)

Highbush blueberry (Vaccinium corymbosum) (N)

Red chokeberry (Aronia arbutifolia) (N)

Red-osier dogwood (Cornus sericea) (N)

Smooth witherod (Viburnum nudum) (N)

Summersweet (Clethra alnifolia) (N)

Spicebush (Lindera benzoin) (N)

Virginia sweetspire (Itea virginica) (N)

Willow (Salix spp.)

Winterberry holly (Ilex verticillata) (N)

Astilbe (Astilbe spp.)

Beebalm (Monarda didyma) (N)

Black-eyed susan (Rudbeckia fulgida) (N)

Blazing star (Liatris spicata) (N)

Blue flag iris (Iris versicolor) (N)

Butterfly milkweed (Asclepias tuberosa) (N)

Cardinal flower (Lobelia cardinalis) (N)

Columbine (Aquilegia canadensis) (N)

Creeping lilyturf (Liriope muscari)

Goat's beard (Aruncus dioicus) (N)

Golden alexander (Zizia aurea) (N)

Great blue lobelia (Lobelia siphilitica) (N)

Japanese iris (Iris ensata)

Joe-Pye weed (Eupatorium fistulosum) (N)

Leopard plant (Ligularia dentata)

Lungwort (Pulmonaria spp.)

Marsh marigold (Caltha palustrus) (N)

Mazus (Mazus reptans)

Mountain mint (Pycnanthemum virginiatum)

Moss phlox (Phlox subulata) (N)

New England aster (Aster novae-angliae) (N)

New York ironweed (Vernonia noveboracensis) (N)

Obedient plant (Physostegia virginiana) (N)

Perennial sunflower (Helianthus spp.) (N)

Queen-of-the-prairie (Filipendula rubra) (N)

Rose mallow (Hibiscus moscheutos) (N)

Siberian iris (Iris siberica)

Sneezeweed (Helenium autumnale) (N)

Spiderwort (Tradescantia virginiana) (N)

Swamp milkweed (Asclepias incarnata) (N)

Sweet woodruff (Galium odoratum)

Tall bellflower (Campanula americana)

Turtlehead (Chelone glabra) (N)

Virginia bluebells (Mertensia virginica) (N)

Woodland phlox (Phlox divaricata) (N)

Japanese bloodgrass (Imperata cylindrical)

Japanese forestgrass (Hakonechloa macra)

Little bluestem (Schizachyrium scoparium) (N)

Lurid sedge (Carex lurida)

Soft rush (Juncus effusus) (N)

Sweetflag (Acorus spp.)

Switchgrass (Panicum virgatum) (N)

Tussock sedge (Carex stricta) (N)

Some of the most drought-tolerant plants for Pennsylvania landscapes (N indicates plants that are native to the mid-Atlantic region)

American hornbeam (ironwood) (Carpinus caroliniana) (N)

American linden (basswood) (Tilia americana) (N)

Ginkgo (Ginkgo biloba)

Goldenrain tree (Koelreuteria paniculata)

Gray birch (Betula populifolia)

Green ash (Fraxinus pensylvanica) (N)

Hackberry (Celtis occidentalis) (N)

Hawthorn (Crataegus viridis and phaenopyrum) (N)

Honeylocust (Gleditsia triacanthos) (N)

Japanese pagoda tree (Sophora japonica)

Japanese tree lilac (Syringa reticulata)

Japanese zelkova (Zelkova serrata)

Kentucky coffee tree (Gymnocladus dioica) (N)

Redbud (Cercis canadensis) (N)

Red oak (Quercus rubra) (N)

Sassafras (Sassafras albidium) (N)

Sawtooth oak (Quercus acutissima)

Serviceberry (Amelanchier canadensis) (N)

Sweetgum (Liquidambar styraciflua) (N)

Sycamore (Platanus occidentalis) (N)

Tulip poplar (Liriodendron tulipfera) (N)

Witch hazel (Hamamelis virginiana) (N)

American yew (Taxus canadensis) (N)

Arborvitae (Thuja occidentalis) (N)

Austrian pine (Pinus nigra)

Colorado blue spruce (Picea pungens)

Cotoneaster (Cotoneaster spp.)

Inkberry holly (Ilex glabra) (N)

Japanese black pine (Pinus thunbergiana)

Junipers (Juniperus spp.) (N)

Mahonia (Mahonia aquifolium, bealei)

Abelia (Abelia x grandiflora)

American cranberry viburnum (Viburnum trilobum) (N)

Arrowwood viburnum (Viburnum recognitum or dentatum) (N)

Bayberry (Morella pensylvanica) (N)

Bearberry (Arctostaphylos uva-ursi) (N)

Beautyberry (Callicarpa spp.)

Beautybush (Kolkwitzia amabilis)

Black chokeberry (Aronia melanocarpa) (N)

Black haw viburnum (Viburnum prunifolium) (N)

Blue mist shrub (Caryopteris x clandonensis)

Bush honeysuckle (Diervilla lonicera) (N)

Coralberry (Symphoricarpos orbiculatus) (N)

Crape myrtle (Lagerstroemia indica)

Deutzia (Deutzia Gracilis)

Eastern sweetshrub (Calycanthus floridus) (N)

Elderberry (Sambucus canadensis) (N)

Fragrant sumac (Rhus aromatica) (N)

Gray dogwood (Cornus racemosa) (N)

Lilac (Syringa spp.)

New Jersey tea (Ceanothus americanus) (N)

Ninebark (Physocarpus opulifolius) (N)

Oakleaf hydrangea (Hydrangea quercifolia)

Potentilla (Potentilla fruticosa)

Red chokeberry (Aronia arbutifolia) (N)

Red-osier dogwood (Cornus sericea) (N)

Shrub rose (Rosa spp.)

Snowberry (Symphoricarpos albus) (N)

Smokebush (Cotinus coggyria)

Smooth sumac (Rhus glabra) (N)

Spicebush (Lindera benzoin) (N)

St. John's wort (Hypericum spp.)

Virginia sweetspire (Itea virginica) (N)

American bittersweet (Celastrus scandens) (N)

Trumpet (scarlet) honeysuckle (Lonicera sempervirens) (N)

Trumpet vine (Campsis radicans) (N)

Virginia creeper (Parthenocissus quinquefolia) (N)

Agastache (Agastache spp.)

American alumroot (Heuchera americana) (N)

Barren strawberry (Waldsteinia fragaroides) (N)

Barrenwort (Epimedium spp.)

Bearded iris (Iris germanica)

Beardtongue (Penstemon species) (N)

Bellflowers (Campanula)

Black-eyed susan (Rudbeckia fulgida) (N)

Blanket flower (Gaillardia aristata, grandiflora)

Blazing star (gayfeather) (Liatris) (N)

Blue star (Amsonia montana) (N)

Blue wood aster (Aster cordifolius) (N)

Boltonia (Boltonia asteroides) (N)

Brown-eyed susan (Rudbeckia triloba) (N)

Butterfly weed (Asclepias tuberosa) (N)

Canada ginger (Asarum canadensis) (N)

Candytuft (Iberis sempervirens)

Catmint (Nepeta spp.)

Creeping lilyturf (Liriope muscari)

Creeping phlox (Phlox stolonifera) (N)

Cup plant (Silphium trifoliatum) (N)

Cutleaf coneflower (Rudbeckia laciniata) (N)

Daylily (Hemerocallis)

Dead nettle (Lamium maculatum)

False indigo (Baptisia australis) (N)

Garden phlox (Phlox paniculata) (N)

Gaura (Gaura biennis) (N)

Globe thistle (Echinops ritro)

Goat's beard (Aruncus dioicus) (N)

Goldenrod (Solidago rugosa) (N)

Hardy geranium (wood geranium) (Geranium maculatum) (N)

Heliopsis (Heliopsis helianthoides) (N)

Hens and chicks (Sempervivum spp.)

Lamb's ears (Stachys byzantina)

Lavender (Lavandula spp.)

Leadwort (Ceratostigma plumbaginoides)

Meadow sage (Salvia spp.)

Moss phlox (Phlox subulata) (N)

New England aster (Aster novae-angliae) (N)

Pale coneflower (Echinacea pallida) (N)

Pinks (Dianthus spp.)

Purple coneflower (Echinacea purpurea) (N)

Queen-of-the-prairie (Filipendula rubra) (N)

Russian sage (Perovskia atriplicifolia)

Sea holly (Eryngium amethystinum)

Sneezeweed (Helenium autumnale) (N)

Spurge (Euphorbia spp.)

Stoke's aster (Stokesia laevis) (N)

Stonecrop (Sedum spp.)

Sunflower (Helianthus) (N)

Tickseed (Coreopsis lanceolata) (N)

White wood aster (Aster divaricatus) (N)

Wild bergamot (Monarda fistulosa) (N)

Wormwood (Artemisia)

Yarrow (Achillea millefolium)

Yucca (Yucca filamentosa)


Big bluestem (Andropogon gerardii) (N)

Blue oat grass (Helictotrichon sempervirens)

Bottlebrush grass (Elymus hystrix) (N)

Indian grass (Sorghastrum nutans) (N)

Little bluestem (Schizachyrium scoparium) (N)

Feather reed grass (Calamagrostis acutiflora)

Prairie dropseed (Sporobolus heterolepis) (N)

Switchgrass (Panicum virgatum) (N)

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