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HomeMy Public PortalAbout498693Metropolitan St. Louis Sewer District Web Site: www.stlmsd.com 24-Hour Hotline 314.768.6260 Metropolitan St. Louis Sewer District Planter Boxes Post-Construction Stormwater Best Management Practice (BMP) Ownership and Maintenance Performance : To ensure proper performance, visually inspect that stormwater is infiltrating properly into the planter box soil and that there is discharge from the underdrain during large wet weather events. Water ponding in a planter box for more than 24 hours may indicate a problem. Native plantings: Because they are more tolerant of the local climate, soil, and water conditions, na- tive plants are recommended for rain gardens. Na- tive plants are preferable to ease maintenance of the planter box. Ponding Water: Following a rain event, it is normal to see shallow puddles in the a planter for a day or two. Resist the urge to fill in these shallow areas. If water is still present after three days, it may be necessary to rake or poke shallow holes in the soil. If water still remains, corrective measures may include inspection for soil compaction and underdrain clogging, replacement of the top layer of soil and mulch, backflusing of the underdrain or replacement of the underdrain and soil. Weeding: When the plants in your planter box are establishing themselves, weed growth is common. Weeding, either by pulling or spot use of herbicides, helps to eliminate weed growth and preserve your plantings. Blanket use of herbicide is NOT recommended. Diligent weeding during the first years typically results in plantings that, by year three, are mature enough to crowd out most weeds. Watering: Mature plants, especially if native plants used, should not require additional watering, ex- cept during periods of drought. Watering is more important during the early stages when plants are still establishing themselves. Trimming & Pruning: Beginning in late winter or early spring, trim plants near the surface with a string trimmer or pruner, and remove dead veg- etation to encourage new growth. Shrubs may be pruned to give them the shape you prefer. Fertilizing: You may wish to fertilize your planter box during the first year to help establish healthy plants. Beyond the first year, fertilizing is unneces- sary because it stimulates weed growth and may reduce water quality benefits. Mulching: A layer of two to three inches of mulch to the surface of your planter box should be in- stalled. Replacing old mulch each spring improves its appearance and drainage. Mulch should be free of soil, weed seeds and herbicide. Pine bark and “chipped” mulch are not recommended for use dur- ing maintenance. Trash: Leaves, lawn clippings, and other trash should be removed as needed. Leaves or grass clippings should NOT be spread in a planter box. Maintenance & Inspection Tips for Planter Box Owners Get to Know Some of the Common Weeds that Should be Removed CASTOR-BEAN COMMON RAGWEED CURLY DOCK JOE-PYE WEED POKEWEED WINTER CREEPER EUONYMUS YELLOW NUTSEDGE Metropolitan St. Louis Sewer District Division of Environmental Compliance 10 East Grand Avenue St. Louis, MO 63147-2913 Phone: 314.768.6260 www.stlmsd.comYour MSD @Your MSD Resources Show Me Rain Gardens www.showmeraingardens.com Missouri Botanical Garden www.mobot.org MSD BMP Toolbox www.stlmsd.com/engineering/planreview/bmptoolbox Planter Box Routine Maintenance Schedule The following outlines typical routine maintenance activities and items to look for when inspecting your planter box: FEBRUARY AND MARCH Remove trash and debris. Prune bushes and trim other plants to near the surface. Remove old, compacted mulch and replace with new mulch. APRIL AND MAY Replace or remove diseased, undesirable or dead plants. Separate or move plants, if desired. Pull weeds. JUNE THROUGH AUGUST Water plants during extremely dry periods. SEPTEMBER AND OCTOBER Remove trash and debris. Replace or remove any diseased, undesirable or dead plants. Pull weeds, but leave grasses and flower in place over the winter. Check for adequate mulch cover. Repair any eroded areas within the planter box. ANYTIME Check for standing water that remains after three days. While not routine, replacement of soil and underdrain may be required during the lifetime of the planter box. Ensure downspout and overflow clear of debris What is a planter box? Every time it rains, stormwater that flows down roofs contributes to higher runoff volume and may transport pollutants to streams and lakes. A planter box is a planted area where rainwater collects. Think of a planter box as a sponge -- an environmentally friendly sponge -- that is designed to soak up much of this runoff before it can do damage. Planter boxes are elevated structures containing plants, shrubs, or trees that are used when roof downspouts can be disconnected from the sewer system and re-directed. Planter boxes offer “green space” that provide a soil/plant mixture suitable for stormwater capture and treatment. Rainfall is retained and stored in the soil within the planter boxes and the vegetation intercepts rainfall. Reduction of pollutants as the stormwater ponds and infiltrates through the planter box soil. Pollutants are absorbed by the soil particles.. Planter boxes can be constructed of various materials including, stone, concrete, brick, synthetic lumber or wood, planter boxes come in all shapes and sizes. Pollutants that are absorbed and degraded through the plants and soil in the planter box include: bacteria, nitrogen, phosphorus, oil, grease and other pollutants. Metropolitan St. Louis Sewer District Web Site: www.stlmsd.com 24-Hour Hotline 314.768.6260 Metropolitan St. Louis Sewer District Benefits Of A Planter Box Improves water quality. The plantings, soil, and gravel in the planter box helps to filter contaminants from stormwater run-off, improving the quality of the water that recharges local groundwater and waterways. Planter boxes are often used in urban environments as stormwater best manage- ment practices to improve water quality. Lowers the volume of water entering public sewer systems. By diverting this water, planter boxes decrease the flow to our wastewater treatment plants during storms, when flow typically peaks. Reduces sewer overflows and flooding. Planter boxes help reduce runoff, which in turn helps to minimize com- bined sewer overflows, localized flooding and erosion. Maintenance Costs The cost for maintaining a planter box is similar to the cost for maintaining a rain garden, which is approximately $4 to $8 per square yd. Additional maintenance costs may be associated with the structural maintenance of the physical planter box. A general rule of thumb to estimate annual maintenance costs is to use 3-6% of the construction costs of the post construction stormwater BMP. Ensuring routine preventa- tive maintenance is completed on a routine basis, will help deter higher costs associated with non-routine restorative maintenance. Native Plants Recommended For Planter Boxes ARROWHEAD SAGIREARIA GRAMINEA 1-2’ JUNE-SEPTEMBER BUTONBUSH CEPHAFANRHUS OCCIDENAFIS 3-6’ JULY-AUGUST CARDINAL FLOWER LOBELIA CORDINALIS 2-4’ JUNE-SEPTEMBER CULVER’S ROOT VERONICASTRUM VIRGINICUM 3-5’ JUNE-AUGUST GIANT BUR-REEDSPARGANIUMEURYCARPUM1-3’ MAY-JUNE GREAT BLUELOBELIA LOBELIA SIPHILITICA 2-4’ AUGUST-SEPTEMBER MOUNTAIN MINT PYCNANTHEMIM VIRGINIANUM 2-4’ JULY-SEPTEMBER NEW ENGLAND ASTER ASTER NOVAE-ANGLIAE 1-5’ AUGUST-OCTOBER PALM SEDGE MUSKINGUMENSIS 1-3’ AUGUST-OCTOBER PRAIRIE BLAZING STARLIATRIS PYCNOSTACHYA2-4’ JULY-SEPTEMBER RIVER OATS CHASMANTHIUM LORIFOLIUM 2-3’ FALL COLOR SNEEZEWEED HELENIUM AUTUMNALE 2-6’ AUGUST-OCTOBER STIFFGOLDENROD SOLIDAGO RIGIDA 2-4’ JULY-OCTOBER