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