Spring 2015
Garden Agreement for the Green Partners Program
As with all Green Partners Environmental Education program activities, garden projects must be
utilized as an environmental engagement tool addressing at least one of the Green Partner topics. To
qualify for Green Partners funding, proposers must receive approval from the property owner or
caretaker, provide a maintenance plan and submit a detailed design plan for rain garden projects.
Educational component
Project managers must ensure the following:
1. Participants are engaged in planning and/or planting the garden.
2. A presentation or tour is developed and presented to community members or visitors.
3. Ongoing educational opportunities for gardens are provided for participants engaged with
garden maintenance.
Garden maintenance
The county requires a garden maintenance plan because it is essential to plan for and follow through
on inspection and maintenance of your garden. However, garden maintenance is not always
considered during the planning phase. Volunteers may be hard to find or summer schedules can
make it difficult to consistently water and weed gardens. This can be a major contributor to
complaints that gardens – particularly rain gardens - appear “unkempt.”
If gardens are not routinely maintained, they will become a patch of weeds after a few years. Rain
gardens will not function effectively if not maintained. Unfortunately, this can harm the image of
community and rain gardens in the public’s mind and defeat the purpose of utilizing the garden as a
learning tool.
Maintenance agreement
Signing this form means you agree to the following:
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The rain gardens funded by the Green Partners program will remain in place and receive ongoing
maintenance for at least 10 years following installation to ensure design integrity and utility as an
educational tool.
The landowner will grant Hennepin County staff access to the property to evaluate the site before,
during and after installation of the garden.
Rain garden plans must be submitted and approved by Environmental Services staff prior to
installation of the garden or if changes are made to the approved design.
Rain garden areas will not be used as dedicated snow storage areas where sand and salt is applied.
Periodic pruning and weeding will occur to maintain garden appearance.
Trash and debris will be removed from the garden whenever present.
Following initial installation, mulch will be replaced when erosion is evident or yearly or biannually to
maintain a depth of 3 inches to inhibit weed establishment.
Inspection of rain garden inlet points will occur on a semi-annual basis. Sediment and debris will be
removed when evident and areas that have been impacted by sand/salt build up will be replanted.
Questions? Contact Patience Caso at 612-348-9352 or Patience.Caso@hennepin.us
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Spring 2015
Maintenance plan
Please provide details regarding the maintenance tasks following installation of the garden. Describe
who is in charge of each task, when and at what frequency these tasks will be performed each year.
Staff lead (name, title):
Volunteers and additional staff support (names, titles/roles):
Task
Staff person or volunteer
Hennepin County garden inspection contact
Spring assessment
Weeding
Watering
Trash removal
Mulch and fertilizer
Silt removal at inlet
Routine replacement of plants
Fall clean up
General plant maintenance – deadheading,
pruning, dividing, stakes and supports, etc.
(Weeding should occur at least twice per year
in the spring and late summer when weed
generation occurs. Plants that are dead or
diseased need to be removed and replaced.)
Timeline
Are funds available to support maintenance of the garden for ten years?
 If yes, is it dedicated funding or general operations funding?
 If not, how do you plan to ensure the maintenance plan is followed?
This garden and maintenance plan has been approved by:
_____________________________________
________________________
Property Owner/Property Manager
Date
Rain garden manual
High-quality rain gardens will be planned and installed in accordance with the methods outlined in the
following documents:
 State of Minnesota Stormwater Manual: www.pca.state.mn.us/index.php/water/water-types-andprograms/stormwater/stormwater-management/minnesotas-stormwater-manual.html
 Plants for Stormwater Design: www.pca.state.mn.us/index.php/view-document.html?gid=5651
Additional resources
 Metro Blooms: www.metroblooms.org, workshops and landscape design assistance available
 The Blue Thumb Guide to Rain Gardens: download at http://bluethumb.org/raingardens or purchase
on Amazon.
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Spring 2015
Hennepin Green Partners Program - Required Rain Garden Documentation
The following information needs to be submitted for county staff to review and approve prior to
proceeding with the construction of a rain garden:
1. A detailed site plan that includes property lines and location of building foundations, utilities and utility
easements, driveways, walkways and paved areas. (Call 811 before you dig: Gopher State One Call)
2. Location of proposed rain garden, which must be located at least 10 feet from a property line or
building foundation (include elevations of existing foundation that are in close proximity to proposed
rain garden).
3. Location of downspouts from buildings and drainage swales that will discharge into the proposed rain
garden.
4. Stormwater calculations that determined the size of the rain garden. Use the following chart for
guidance if rain garden will be capturing runoff from a rooftop. (Each 100 square feet of roof area will
need a minimum 3.5’ x 3.5’ x 1’-deep rain garden.)
Roof Square Footage (square feet)
100
300
500
1000
Rain Garden size (feet)
3.5 x 3.5 x 1
6x6x1
8x8x1
11 x 11 x 1
5. Profile/Cross-section view of rain garden that depicts length and width. Indicate depth of rain garden.
(Note: overall depth of the rain garden must not exceed 1 foot.) Profile and plan must specify elevation
of inlet and outlet. Rain garden plan must identify location of inlet and outlet.
6. Identify source of emergency overflow (i.e., will rain garden outlet discharge to an alleyway, existing
storm sewer inlet, drainage tile, etc.).
7. Provide general description of existing soils (approximate percent of sand, silt, and clay). Identify
depth of soil to be removed (in inches) and what type of rain garden soil mix will be used (ideal rain
garden soil mix is 50 – 60% sand, 20 – 30% topsoil, 20 – 30% compost; no more than 10% of mix
should be clay.) Remember that final depth of rain garden after deposit of soil mix should not exceed
1 foot.
8. Provide rain garden planting plan with list of plant species and quantities.
9. Provide a signed Garden Agreement that includes a maintenance plan that specifies how the rain
garden will be maintained over time. Include frequency of weeding, watering and replacement of
wood chip mulch if used.
Questions? Contact Patience Caso at 612-348-9352 or Patience.Caso@hennepin.us
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