Conservation Landscaping for Healthy Streams Blue Water Baltimore s Guide to Conservation Landscaping in Urban and Suburban Environments Contents Purpose of Conservation Landscaping for Healthy Streams...1 Water Audit Program Rebate Standards...2 Planning Your Conservation Landscaping Project...3 Understanding and Amending Soils...8 Installing Your Conservation Landscaping Project... 12 Use of Native Plants... 15 Maintaining Your Conservation Landscape... 17 Resources... 18
Purpose of Conservation Landscaping for Healthy Streams Conservation Landscaping for Healthy Streams is intended to assist participants of Blue Water Baltimore s Water Audit Program in completing the Conservation Landscaping Project Approval Form and qualifying their project for the conservation landscaping rebate. The rebate is available to residents within the four watersheds located in and around Baltimore City: Gwynns Falls, Jones Falls, Herring Run, and Direct Harbor. Through 2012, the Water Audit Program can reimburse half the cost of a conservation landscaping project up to $300. In order to receive a rebate, residents must register for the program and have their property assessed by Blue Water Baltimore before the project is installed. For more information about Blue Water Baltimore and updated information about the Water Audit Program, visit www.bluewaterbaltimore.org. Blue Water Baltimore created the Water Audit Program to assist homeowners in reducing the negative impact their properties have on the natural environment. Of particular concern in the Baltimore area is the water that runs off of hard (impervious) surfaces such as roofs and roadways. In urban settings, even green spaces can generate this runoff because of soil compaction. This runoff carries trash, chemicals, sediment, and heat into our streams and is often referred to as polluted runoff or stormwater. Stormwater is conveyed directly to local streams and the Chesapeake Bay without being treated. By converting some, or all, of your yard to conservation landscaping, which can capture and infiltrate stormwater, you will be protecting the health of your local streams, the Baltimore Harbor, and the Chesapeake Bay. Prunus americana is a fragrant small tree with bright red fruit in autumn. Monarch butterfly on Asclepias incarnata. Monarch butterflies migrate from Canada to South America. During their long journey they require food and resting places.with the addition of the right plants, your conservation landscape can be a butterfly habitat. Because a primary goal of the Water Audit Program is to reduce the amount of pollution in our urban streams and the Chesapeake Bay, the rebate standards place a particular emphasis on reducing runoff. In other contexts, an emphasis on different conservation landscaping practices may be warranted. Consequently, this guide is not intended to be an exhaustive guide to conservation landscaping practices. www.bluewaterbaltimore.org Page 1 of 19
Water Audit Program Rebate Standards To qualify for a rebate under the Water Audit Program, conservation landscape projects must meet ALL of the following specifications: 1. The property on which the project is completed must be located within the Gwynns Falls, Jones Falls, Herring Run, or Direct Harbor watershed (see map below); 2. The project area must measure at least 100 square feet (or, alternatively 100 percent of the available space in yards smaller than 100 square feet); 3. The project area must currently be covered with turf grass, invasive plants, and/or consist of exposed soil; 4. The soil within the project area must pass two of the three soil tests (compaction, percolation, and soil type as outlined herein) or, if it fails two or more tests, be amended with at least two inches of leaf compost or other organic soil amendment; 5. Upon completion of the project, the project area must either be level with or concave to the surrounding ground surface (exception is available for steep slopes and hillsides); 6. Upon completion of the project, at least 80 percent of plants in the conservation landscape must be native to the mid-atlantic region (native cultivars are acceptable); and 7. Upon completion of the project, the project area must be covered with one to two inches of plant based mulch. Blue Water Baltimore s watersheds. www.bluewaterbaltimore.org Page 2 of 19
Planning Your Conservation Landscaping Project You may be tempted to start your conservation landscape planning with plant selection. However, before you begin choosing plants, you must first choose a location and then gather information about that location so that you can choose the right plants. To qualify your project for a rebate, the location must reduce runoff from your property. Typically, a landscape that reduces runoff is located downhill from impervious surfaces and is level with or concave to the surrounding ground, thereby maximizing the interception and infiltration of runoff. Your landscape planning process should consider your use of the space, the topography, existing landscaping, and other site conditions. Once those factors are evaluated, then you can begin selecting plants and constructing your planting plan. Native vines such as Wisteria frutescens are great for providing shade below a pergola or hiding ugly amenities such as air conditioners or heat pumps. Use of Space Begin by looking at the property as a whole, and then focus on the appropriate location for your conservation landscape. Group locations on the property into general categories. For example, if you have set aside an area for vegetable gardening or as a play area for children, this area might not be appropriate for conservation landscaping. Alternatively, areas where you have had trouble growing grass or other plants, areas downslope from your house and lawn but upslope from the street, or lawn that you no longer want to mow, might be considered good locations for conservation landscaping. In urban environments, where properties tend to be smaller, this may be a relatively easy process. Larger properties, however, may have multiple ideal conservation landscaping locations. On larger properties select a location with the greatest water interception and infiltration opportunity. Topography Well-placed conservation landscaping can benefit the health of your watershed by absorbing runoff from a surface such as a lawn, roof, patio, or driveway. To the extent possible, select a site for conservation landscaping that is downhill from such surfaces. Maximize the amount of water absorbed by shaping the ground to be concave where the landscape will be planted. Recessing rather than mounding your landscaping will also lessen your irrigation needs, thereby conserving potable water resources, as well as saving you time and money. If you are planning a conservation landscape for a steep slope, consider terracing or planting with dense perennials, particularly those with evergreen leaves and dense stolons (the base stem of the plant). Terrace steps should be no more than 30 inches in height unless a retaining wall is installed. Steep slopes should not www.bluewaterbaltimore.org Page 3 of 19
be left with bare soil or expanses of exposed mulch, because the material is likely to erode during rain events. Should the material erode, your landscape will be adding to our stormwater problem rather than reducing it. Existing Trees & Landscaping The limbs and roots of existing trees may influence the amount and type of conservation landscaping as well as the technique for soil amendment that is appropriate for a particular site. Keep in mind that this influence may vary by tree species. For example, maple and birch trees tend to have extensive and shallow root systems. It can be challenging to perform landscaping work under these trees without damaging them. Additionally, these trees draw large amounts of water from the soil, creating dry conditions under their canopies. If you are landscaping near or under a tree, identify the tree species and conduct your own research as to the conditions that result from the tree s presence. Roots from most tree species extend beyond the canopy edge. If you are landscaping under or near an existing tree, minimize damage to the existing root structure by avoiding the use of heavy machinery Typical root structure and dripline of a canopy tree. Source: Connecticut Agricultural Experiment Station; http://www.ct.gov/ and by tilling or cutting roots as little as possible. In general, Blue Water Baltimore does not recommend amending soils by top-dressing, but an appropriate exception is below established trees. It is also important not to bury existing roots beneath thick layers of soil or mulch since tree roots depend on air to survive. When working close to existing trees, Blue Water Baltimore recommends that you consult a certified arborist before planning or beginning work to ensure that healthy trees remain so and that damaged trees are appropriately trimmed or removed. Take an inventory of the existing plants in your yard so that your conservation landscape can complement your existing landscape. Consider how tall they grow, when they bloom, how much water and sunlight they need, and the soil conditions they prefer. If those established plants are thriving, select new plant species with similar characteristics. This way, your new plants are more likely to establish quickly and you may be able to minimize long-term maintenance and expense. For example, if you have a bed with acid-loving plants like azaleas or roses you could extend that theme by planting native blueberries or winterberry hollies rather than trying to plant a species that prefers neutral soil. If the area you have identified includes an invasive species, you may need to take drastic action to eliminate the existing vegetation before you plant your conservation landscape. Invasive species that are particularly difficult to eliminate are running bamboo and English ivy. For tips on how to identify and best eradicate invasive species, see the Resources section at the end of this document. www.bluewaterbaltimore.org Page 4 of 19
Other Site Conditions You will need to gather other information such as sun exposure, average soil moisture and ph, and the location of utility lines. Your site will fall into one of the broad categories of full sun, partial sun/partial shade, or full shade. Estimate the number of hours of daylight in your selected location. Note the time that sunlight first hits the location and then when the area returns to shade. The total time in sun may be interrupted during mid-day due to existing plant material that only casts a shadow during certain parts of the day or times of the year. Keep in mind that sun exposure varies throughout the year due to the tilt of the earth and dropping of deciduous tree leaves. The best time to measure sun exposure is between the beginning of May and the end of July. Heuchera sp. and Tiarella sp. are good plants for full shade locations. Full sun: at least six hours of direct sunlight every day Partial Sun or Partial Shade: between three and six hours of direct sunlight every day Full Shade: less than three hours of direct sunlight every day Soil moisture is likely to vary with the weather. However, a site may be constantly wet due to an underground spring or a sump pump discharge point, or consistently dry due to intense sun exposure. Exact soil ph can be requested when your soil sample is sent for nutrient and soil type analysis. See Understanding and Amending Soils on page 8 and the Resources section at the end of this document for more information about testing soils. Utility conflicts are primarily a concern for trees and digging. When digging, be sure to avoid any buried wires, and refrain from digging deep with heavy equipment around buried pipes. Most trees should not be planted below overhead wires or directly above pipes. Generally, trees with a mature height of less than 25 feet may be safely planted under overhead utility lines, while taller trees should be planted at least 20 feet from the lines. Additionally, canopy trees should not be planted directly on property boundaries. Plant your tree so that a significant majority of the mature canopy will remain above your property. Whenever possible, plant canopy trees on the south or southwest side of the house to provide shade to the building during the summer months. For more information on tree planting, see the Resources section at the end of this document. Even if you are not planting trees or using heavy equipment, Blue Water Baltimore recommends that the site be marked by relevant utility companies. To have your property marked call MISS Utility at 811 or schedule your property marking at www.missutility.net. This is a free service for residents. www.bluewaterbaltimore.org Page 5 of 19
Create a Planting Plan Now that you know more about your site, you are ready to draw up your planting plan. Begin by sketching out your site with accurate dimensions. A planting plan will help you to visualize your finalized landscape and budget for the number of plants needed. The sample planting plan below begins with existing conditions and dimensions; then, a sketch of the area to be planted is added, and lastly plants are added. The easiest way to draft planting plans is on graph paper. Step 1: Sketch out your yard with existing landscaping, trees, fences, utilities, and other characteristics. Step 2: Sketch out the area to be landscaped, including dimensions. www.bluewaterbaltimore.org Page 6 of 19
Choose from plants listed in the Native Plants section of this document and from other resources, some of which are listed in the Resources section at the end of this document. When selecting plants for your landscape, be sure to take into account their mature size height and width as well as recommended planting distances. Step 3: Pick out your plants based on site characteristics and your personal preferences. Step 4: Sketch out plant location and number of plants. Clumping plants of the same species is one way to add consistency to your landscape. www.bluewaterbaltimore.org Page 7 of 19
Understanding and Amending Soils Soil Characteristics and the Benefits of Healthy Soils Soils tend to fall into that out of sight, out of mind category. We often only take note when there is a problem such as erosion or unhealthy plants. However, healthy soils provide critical ecosystem services such as absorbing rainfall and filtering pollution as well as providing a growing substrate and nutrients for plants. Soils that can effectively absorb, or infiltrate, rainfall keep our streams flowing during dry weather. Conservation landscaping is one of the strategies employed by Blue Water Baltimore to achieve healthy soils in our watersheds and improve the health of our streams. Rain gardens are even more effective at capturing and infiltrating runoff. For more information on rain gardens, visit www.bluewaterbaltimore.org. Compaction Urban soil is often compacted to the point that it is essentially impervious. Compaction is common in the Baltimore region given the high clay content in the soil and modern construction techniques. Causes of compaction include the use of heavy equipment and repeated foot traffic. Blue Water Baltimore s goal is to ensure that the soil in conservation landscapes has the ability to absorb as much water as possible thereby reducing stormwater. Hydrologic Soil Group Classification Blue Water Baltimore is specifically interested in the rate at which water enters the soil at the soil s surface. If water enters, or infiltrates, the soil then it does not, by definition, run off of the soil. The National Resources Conservation Service uses a Hydrologic Soil Group classification scheme to characterize a soil s ability to absorb water: Group A: soils absorb water quickly (more than 0.3 inches per hour), and very little water runs off even when wet. These soils tend to have a high sand content. Group B: soils absorb water at a moderate rate (0.15 to 0.30 inches per hour), and are colloquially considered to be moderately well drained or well drained soils. Group C: soils have a low infiltration rate (0.05 to 0.15 inches per hour). These soils absorb water poorly, and can produce significant runoff. Group D: soils produce very high amounts of runoff. These soils absorb water very poorly (0-0.05 inches per hour) and tend to act as an impervious surface. www.bluewaterbaltimore.org Page 8 of 19
Group A and Group B soils capture the most rain water, recharging groundwater supplies and helping to feed streams between rain storms. Group C and Group D soils contribute to flooding and result in less stable water flow in streams. For the purposes of completing the Conservation Landscaping Project Approval Form, there is no need to determine the exact hydrologic group classification. Instead, use a percolation test (described below) to determine if your soils do, or do not, drain sufficiently. Soil Texture Classification One of the most commonly used soil classification systems is based on soil texture (see the chart on the right). The relative proportions of sand, silt, and clay dictate the final classification. Sand is the largest particle size, silt is a medium particle size, and clay is the smallest particle size. Most soils have a mix of these three particle sizes, and Baltimore s natural soils generally fall into the clay loam category on this scale, found in the middle of the classification triangle. It is important to note, however, that urban soils often have a large percentage of fill dirt, meaning that the soil was not built up naturally. These soils tend to be high in clay content and are likely to be compacted. Soil texture classification triangle Source: Natural Resources Conservation Service: http://soils.usda.gov/education/resources/lessons/texture/ Determine if Soils Need to be Amended It is important to understand the soil type and infiltration capacity for each particular project area. Therefore you will need to test the soil for its level of compaction, infiltration rate, and texture or composition. The results of these tests will help you determine whether amending the soil in your particular project location is necessary. Nearly half of the soil in Baltimore falls into Hydrologic Soil Groups C or D, so it is likely that your conservation landscaping project will require soil amendments in order to qualify for a rebate through the Water Audit Program. More information about soil testing is available in the Resources section of this document. www.bluewaterbaltimore.org Page 9 of 19
1. Test for compaction Specialized equipment is needed to get a truly accurate estimate of soil compaction. For the purposes of the Water Audit Program, low-tech qualitative observations will allow you to decide if your soils fall into one of two broad categories: compacted or not compacted. Blue Water Baltimore recommends that you use the screwdriver test. 1) When soils are moist, insert a large screwdriver into the soil. The amount of force used is relative to individual capabilities, but think of what it would take to push the screwdriver through play-dough or wet sand at the beach. Be sure that the soil is neither saturated nor dry. This test should be repeated at several locations, as a rock may impede the screwdriver. a) If it is easy, then the soil is not compacted. b) If it is difficult, then the soil is likely compacted. 2. Test for infiltration You will not need to determine which Hydrologic Group your soils fall into, a percolation test will adequately evaluate the soil s ability to absorb, or infiltrate, water. Test in multiple locations if the conservation landscape project spans areas with significantly different characteristics, includes multiple non-adjacent areas, or if the project covers more than 250 square feet. Ideally, a percolation test will be performed when the ground is saturated, or just following a significant rain storm. 1) Dig a hole 12 inches deep and 12 inches in diameter. 2) Fill the hole with water. 3) Return after an hour or two and fill it again. 4) Within 6 hours of the hole draining completely, fill the hole with water a third time. 5) Check the hole several times over 24 hours after the final filling of the hole. If there is still water in the hole after 24 hours, then the soil did not pass the percolation test. 3. Test for soil texture and/or composition It may be possible to estimate the soil texture yourself using visual clues and touch. For more information and directions for performing the feel test, see Resources section at the end of this document. In most cases, Blue Water Baltimore recommends a scientific soil test. In urban settings, if your soil is more than 50 percent clay, then it is likely poor at infiltrating water. A scientific test will not only give you an accurate analysis of soil texture and ph, but it will also reveal whether the soil has abnormal levels of nutrients or contaminants. If you are growing food to eat, you may want to have the lab also test for heavy metals, such as lead, which are commonly found in urban soils. www.bluewaterbaltimore.org Page 10 of 19
How & When to Amend Your Soils You will need to amend your soil if it fails two of the three tests listed above. However, it is important to keep in mind that tilling healthy soil will destroy its existing structure. If the existing soils pass two of the three tests, top-dress rather than till when amending soils. Top-dressing is the application of one inch or less of soil amendment to the surface of the ground where it will be slowly incorporated into the existing soils by the actions of invertebrates such as earthworms. Top-dressing can be combined with turf removal, but no matter when amendment is added to the surface of the soil, be sure that it is not able to wash away. Top-dressing can be repeated year after year to continually add organic matter and nutrients to the soil. When you leave leaf litter in place, your conservation landscape will effectively top-dress and amend itself. Amend your soil prior to planting, and plan on adding additional amendments to the holes when planting. In most cases, adding approximately two inches of compost and incorporating it into the soil to a depth of four to six inches will adequately increase the ability of your soil to infiltrate water. However, if your soil fails all three tests, you may decide to take more drastic action. Some options, ranked from highest effectiveness (and highest level of effort) are: Remove all of your clay soil to a depth of six inches and replace with a mix of 30-50% compost, and 50-70% low-clay content topsoil. The soil should be pre-mixed and can be delivered to your site. Remove three inches of the existing soil. Replace the removed soil with a mix of 50% aged shredded hardwood mulch and 50% compost, and incorporate it to a depth of four to six inches. Do not remove soil, but add two inches of aged shredded hardwood mulch and two inches of compost, then incorporate to a depth of four to six inches. This option is only suggested if the area is already recessed in comparison to surrounding ground or when turf and a layer of soil are removed using a sod cutter. Take into account the fact that adding soil and compost without removing existing soil will raise the level of your landscape. If adding soil will cause your conservation landscape to no longer qualify for the Water Audit rebate, remove some soil or re-grade the site to be concave or flat. If this is not possible, a berm along the downhill edge of your landscape is an option to consider. In almost every case, the best soil amendment for improving drainage is one high in organic matter such as compost. Adding organic matter improves the structure of the soil, thereby increasing the availability of water, air and nutrients for plants. Blue Water Baltimore uses Leafgro, high-quality compost produced from grass clippings and leaf waste in Montgomery County, Maryland. Other potential amendments are mulch or coarse sand. If using mulch, be sure to use aged hardwood varieties, not raw woodchips as they rob the soil of nutrients as they decompose. Sand does not provide the nutrients of compost or mulch, but it does provide additional structure to the soil. When adding sand, be sure to use coarse sand. Do not use playground sand, as it will bind with the existing soil particles to form a concrete-like substrate. If your soil is rocky, leave the rocks because they provide soil structure, prevent compaction, and improve infiltration capacity. www.bluewaterbaltimore.org Page 11 of 19
Installing Your Conservation Landscaping Project Eliminating Grass There are three physical (nonchemical) ways that Blue Water Baltimore suggests for removing grass: sheet mulching, sod cutting, and tilling. Select the method that is best for you based on your site conditions, timeline, and budget. Sheet Mulching (also known as the Smother and Cover Method or the Lasagna Method ) is the most natural and inexpensive way to kill turf grass. This method requires a minimum of two to four months, the longest time period in comparison to the other methods outlined here-in. Sheet mulching requires few resources and takes advantage of organic matter that may have been built up by existing vegetation. This is a good option if you start a project in the spring or fall and plan to finish the project the following fall or spring, respectively. To sheet mulch your project area, place a decomposable physical barrier such as wet newspaper or cardboard over the grass or weeds. Then cover it with thick a layer of mulch, three to four inches. Starved for light and air, the unwanted plants will eventually die. After a few months, dig planting holes through the sheet mulch and install the native plants in your new conservation landscape. If your project area is already level with the surrounding ground, this method will raise the area above the existing grade. In order to qualify for the rebate, the new conservation landscape must be level with or lower than the surrounding ground. If this occurs, be prepared to regrade the site before you plant it. Use of a sod-cutter is the quickest of the three methods outlined in this manual. One benefit of using a sod cutter is that it creates a natural depression that collects runoff. Gas powered and manual sod cutters are available for rent from many hardware and equipment rental businesses. Removing the turf altogether eliminates a good portion of un-germinated weed seeds, and may therefore minimize future weed pressure on your conservation landscape. This method will result in a slightly recessed area for your new landscape, which is ideal for stream-friendly conservation landscaping and required in order to receive a conservation landscape rebate through the Water Audit Program. A Blue Water Baltimore team replacing the soils at a residential yard in Baltimore City s Lauraville neighborhood. www.bluewaterbaltimore.org Page 12 of 19
Eliminating turf grass with a rototiller or double digging are time- and labor-intensive techniques. However, primary benefit is that no soil or organic materials are removed from the site. Double digging is the process of loosening two layers of soil and replacing the top layer with the bottom layer and vice versa. Be aware that tilling or digging conserves the organic matter in the topsoil but also preserves the weed seeds. Amend soils and modify topography Depending upon how you have chosen to amend your soils, the amendment process may take place in conjunction with turf removal. If not, now is the time to amend your soils, before you plant and as you are modifying the topography of the project area to maximize the interception of runoff from uphill impervious surfaces and lawn. Erosion control While you are installing your project, prevent exposed soil from washing away by diverting water away from the area. You can do this by putting in landscape edging or laying straw bales around the uphill side of the project. Cover the site and all exposed soil with tarps and place straw bales or silt fencing downhill from the site to prevent the soil from washing away and becoming a pollutant. Avoid compaction Avoid compacting your soil so that your plants remain healthy and your landscape maintains its ability to absorb rainwater. Reduce the likelihood of compaction during the installation phase by laying down boards in a way that allows access to the project area but distributes your weight over greater areas of the soil. Ideally, boards should be six to eight inches wide and at least four feet long. You can also reduce compaction over the lifetime of your landscape by placing stepping stones strategically throughout your landscape and by adding mulch annually to heavily trafficked areas. Planting When planting, place the specimen into the soil so that the top of the root ball or soil in the pot is level with the surrounding soil. If in doubt, plant higher rather than lower, as plants will settle. Add extra soil amendment to the planting hole to give your plants an extra nutrient boost as they are getting established. Avoid covering the stem with soil or mulch, as it will damage the plant. Refer back to your planting plan to determine which specimens are planted where and the ideal plant spacing. Students planting at a Blue Water Baltimore City School project. www.bluewaterbaltimore.org Page 13 of 19
Mulching & Fertilizing Mulching is an important part of helping your landscape to thrive. Mulch conserves soil moisture, reduces the number of weeds, helps prevent erosion, keeps plant roots cool, breaks down to build soil, and provides winter protection. Use organic and natural mulches, not dyed, rubber or other synthetic mulch materials. In an undisturbed ecosystem, nature provides a constant supply of mulch and fertilizer in the form of leaves and fallen branches. Therefore, it is best to leave leaf litter and dropped branches where they fall in your landscape. The decomposition of these materials adds nutrients and organic content to the soil. Leaf litter also serves as a blanket for the soil and plants during the winter, protecting them from harsh weather and fluctuating temperatures. For most new landscapes, however, this process needs assistance. If compost has been used to amend the soils, it will serve as a nutrient base for new landscapes, minimizing the need for additional fertilizer application. Monarch butterfly caterpillar preparing to enter the chrysalis phase on Asclepias incarnata. Blue Water Baltimore recommends mulching a finished conservation landscape with one to two inches of aged shredded hardwood mulch. However, other plant material mulches such as straw, leaf mulch and wood chips may be utilized. Remember not to mound or leave the mulch adjacent to plant stems. As your landscape is getting established, mulching may be required once every one or two years to suppress weeds and build soils. However, a mature conservation landscape needs minimal mulching. Irrigation Irrigate deeply immediately after planting and mulching your new landscape. Typically, one to two hours of watering is sufficient, however the time needed may depend on your water pressure and the size of the area you are irrigating. Periodically check the soil moisture below the mulch layer. The ideal depth of moisture is to four inches. You can put out a rain gauge if you are watering using a sprinkler. One inch of overhead watering is usually sufficient to saturate the soils significantly. Even if you are using a rain gauge, check the soil moisture. Once you have repeated this process a few times, you will know about how long you will need to irrigate in order to deliver enough water to your plants. During the first year or two, between April and October, water your landscape deeply and regularly. Approximately once or twice a week during dry periods will suffice. Leave your rain gauge out and check it to see how much precipitation has fallen in your yard. When precipitation is less than an inch a week, consider irrigating. You can also check the moisture of the soil at around four inches. If they are moist, you do not need to irrigate. The ideal time to irrigate is early morning, between 5:00 and 7:00 am. Watering at this time of day minimizes loss to evaporation and reduces the likelihood that your plants will suffer from mold and fungus which thrive in cool moist environments. Once plants are established, you will only need to irrigate during extremely dry or hot periods of weather. www.bluewaterbaltimore.org Page 14 of 19
Use of Native Plants Native plants are the most important component of conservation landscapes. Native plants are generally superior to non-native plants in their ability to host attractive wildlife and support valuable beneficial insects and pollinators. They are adapted to local soils and climate, and also work with the soil to reduce the amount of polluted stormwater. Many native plants, especially herbaceous meadow plants, have extensive root systems. These roots facilitate the infiltration of water into the ground. A portion of the root system dies back each year, creating pores for air, nutrients and water to move through the soil. These deep roots also allow native meadow grasses and wildflowers This diagram depicts the root systems of common Midwestern prairie plants. Mid-Atlantic native plants have similar root systems. Source: Heidi Natural Conservation Research Institute, http://www.il.nrcs.usda.gov/technical/plants/npg/npg-rootsystems.html to withstand periods of drought. Typical lawn grasses have root systems only a few inches long (the left-most plant in the diagram above). Our native ornamental switchgrass, in contrast, has roots that can extend nearly ten feet deep (when growing in healthy soils). Lastly, conservation landscapes utilizing native plants tend to require less maintenance than lawns and nonnative landscapes because they do not need to be mowed and, once established, rarely need to be irrigated, treated for diseases, or fertilized. Trees are an integral part of our natural ecosystem and a valuable asset to conservation landscapes. Trees shade our homes, provide habitat for wildlife, and clean our air and water. Consider planting trees as well as shrubs and perennials as part of your conservation landscape. On the following page is a list of native plants identified by Blue Water Baltimore as readily available and easy to establish in the Baltimore region. Use this list as you are creating your planting plan, however it is not an exhaustive list. For more information on native plants and additional resources, please see the Resources section at the end of this document. www.bluewaterbaltimore.org Page 15 of 19
Site Conditions Groundcovers Perennials & Grasses Shrubs Sun to Partial Sun & Dry Antennaria plantaginifolia Plantain-leaf pussytoes Cerastium arvense Field chickweed Phlox subulata Moss phlox Sporobolus heterolepis Prairie dropseed Vaccinium angustifolium Lowbush blueberry Asclepias tuberosa Butterflyweed Baptisia australis Wild blue indigo Echinacea purpurea Purple coneflower Panicum virgatum Switchgrass Penstemon digitalis Foxglove beardtongue Penstemon laevigatus Eastern smooth beardtongue Rudbeckia fulgida Black -eyed Susan Schizachyrium scoparium Little bluestem Solidago rugosa* Wrinkleleaf goldenrod Symphyotrichum laeve var. laeve Smooth blue aster Ceanothus americanus New Jersey tea Comptonia peregrina Sweet fern Hypericum densiflorum Dense St. John s wort Ilex glabra* Inkberry holly Morella cerifera Southern bayberry Morella pensylvanica Northern bayberry Photinia melanocarpa* Black chokeberry Rhus aromatica Fragrant sumac Vaccinium corymbosum Highbush blueberry Sun to Partial Sun & Moist Chrysogonum virginianum Green & gold Phlox stolonifera Creeping phlox Conoclinium coelestinum Blue mistflower Chelone glabra White turtlehead Eupatorium dubium Joe-pye weed Lobelia cardinalis Cardinal flower Lobelia siphilitica Great blue lobelia Monarda didyma Beebalm Cephalanthus occidentalis* Buttonbush Clethra alnifolia Sweet pepperbush Cornus racemosa Gray dogwood Itea virginica* Virginia sweetspire Ilex verticillata Winterberry holly Physocarpus opulifolius* Ninebark Shade to Partial Shade & Dry Carex appalachica Pennsylvania sedge Heuchera americana American alumroot Sedum ternatum Mountain stonecrop Aquilegia canadensis Eastern red columbine Chasmanthium latifolium Northern woodland oats Dryopteris marginalis Eastern wood fern Eurybia divaricata White wood aster Hamamelis virginiana Witch hazel Rhododendron atlanticum Coastal azalea Rubus odoratus Purple flowering raspberry Viburnum acerifolium Maple-leaved viburnum Shade to Partial Shade & Moist Asarum canadense Wild ginger Tiarella cordifolia* Foam flower Phlox divaricata Woodland phlox Pachysandra procumbens Allegheny spurge Mertensia virginica Virginia bluebells Osmunda cinnamomea Cinnamon fern Osmunda regalis Royal fern Tradescantia virginiana Virginia spiderwort * Adaptable these plants may tolerate various light and/or moisture conditions Clethra alnifolia Sweet pepperbush Ilex verticillata Winterberry holly Lindera benzoin Spicebush Viburnum dentatum* Southern arrowwood Viburnum prunifolium* Black haw www.bluewaterbaltimore.org Page 16 of 19
Maintaining Your Conservation Landscape Weeding Your conservation landscape will need to be weeded periodically. The more weeds removed in the first two years, the less weeding you will have to do in the following years. The good news is that over time your plants will grow and spread, shading out the weeds. Be sure to mark your plants if you are not familiar with them to avoid accidentally pulling them out. Keep in mind that while it may take more time and be more expensive to plant densely when your project is installed, these plants will shade and out-compete weeds sooner, minimizing the need for extra work on your part in years to come. Fertilizing A well-maintained landscape of native plants will seldom, if ever, need to be fertilized after it is established. This is especially true if a low-impact approach to maintenance is employed, by allowing the leaves and stems of dormant plants to remain standing through the winter and not raking or otherwise disturbing the surface layer of your landscape. When left alone, plant material breaks down, returning nutrients to the soil. Before applying any fertilizer to any landscape, including lawns, Blue Water Baltimore suggests that homeowners test their soil for nutrient levels and/or consult with a gardening professional. More information on soil testing can be found in the Resources section at the end of this document. In many cases, if a plant appears to be under stress it will likely be harmed not helped by fertilization. Moreover, fertilizing a landscape tends to encourage annual weeds rather than boost the growth of established native perennials, trees, and shrubs. Furthermore, the excess application of fertilizer by homeowners is a leading cause of pollution in the Chesapeake Bay. If fertilization is needed, use natural slow-release fertilizers such as bone meal, cottonseed meal, kelp, greensand, or composted garden manure. You may also top-dress your landscape with leaf compost or another soil amendment. Whenever you top-dress or fertilize, be sure to minimize erosion and runoff. Organic matter and nutrients are good for plants, but they are also primary culprits in the degradation of our streams and the Chesapeake Bay, so be sure to apply them in a responsible manner. Growing and Modifying Your Landscape As your landscape matures, you may identify new areas for planting. Your plants will naturally spread, but to speed up the process, many perennials can be propagated by carefully dividing the plant crown and root mass. If you propagate or transplant your plants, be sure to do this during the spring or the fall, followed with generous watering. Expanding your conservation landscape can take place over time. Phasing in additions to your landscape will give you the time needed to keep the expanded areas free of weeds and ensure the establishment of new plants. www.bluewaterbaltimore.org Page 17 of 19
Resources Yard Certifications: For residents interested in doing more, there are several programs available for wildlife and watershed friendly yard certification. Bay-Wise Certification Bay-Wise Certification is a program of the Maryland Master Gardeners, who are organized by jurisdiction. A Master Gardener will come to your property, assess many characteristics, and then rate them, giving your yard a score. An up-to-date contact list is available at: www.mastergardener.umd.edu. Backyard Habitat Certification Program National Wildlife Federation s Wildlife Habitat Certification Program includes checklists to ensure that your yard has all the essential elements to provide resources for wildlife. More information is available at: www.nwf.org/certifiedwildlifehabitat/. Maryland s Wild Acres Wild Acres is Maryland Department of Natural Resources voluntary program which encourages Maryland citizens to create backyard wildlife habitat. The goal of the Wild Acres program is to encourage landscapes across the State that maximize wildlife benefits and highlight conservation stewardship. This is not a certification program. More information is available at: www.dnr.state.md.us/wildlife/habitat/wildacres/. Plant and Landscaping Resources: Blue Water Baltimore recommends the following resources for people new to native plants and conservation landscaping. Arbor Day Foundation Right Tree, Right Place http://www.arborday.org/trees/righttreeandplace/righttree.cfm Chesapeake Conservation Landscaping Council Conservation Landscaping Guidelines: The Eight Essential Elements of Conservation Landscaping http://www.chesapeakelandscape.org/ Rudbeckia fulgida or black-eyed Susans bloom all season and do well in sunny areas. National Park Service & United States Fish and Wildlife Service Plant Invaders of Mid-Atlantic Natural Areas http://www.nps.gov/plants/alien/pubs/midatlantic/midatlantic.pdf www.bluewaterbaltimore.org Page 18 of 19
University of Maryland Extension Service Home and Garden Information & Send-a-Question http://www.hgic.umd.edu/index.cfm United States Fish & Wildlife Service Native Plants for Wildlife Habitat and Conservation Landscaping: Chesapeake Bay Watershed http://www.nativeplantcenter.net/ Soil testing and amendment resources: For more information on testing, assessing, and amending soils. Colorado State University Estimating Soil Texture http://cmg.colostate.edu/gardennotes/214.pdf Natural Resources Conservation Service Technical classification of soils http://soils.usda.gov/technical/classification/ Understanding soils http://soils.usda.gov/ Hydrologic Soil Classification http://www.cpesc.org/reference/tr55.pdf Guide to Texture by Feel http://soils.usda.gov/education/resources/lessons/texture/ United States Forest Service Wilderness Site Restoration http://www.fs.fed.us/t-d/pubs/htmlpubs/htm06232815/page04.htm A freshly planted conservation landscape in Baltimore. Species clockwise from left: Echinacea pallida, Monarda fistulosa, and Asclepias tuberosa. University of Maryland Soil Maintenance Guide http://www.hgic.umd.edu/content/soil.cfm Soil Amendments and Soil Testing Laboratories http://www.hgic.umd.edu/content/documents/hg42_002.pdf http://www.hgic.umd.edu/content/soiltesting.cfm. Virginia Tech Mulching for a Healthy Landscape http://pubs.ext.vt.edu/426/426-724/426-724.html www.bluewaterbaltimore.org Page 19 of 19