§ 18A-6. Minimum standards.
The following standards shall be considered minimum requirements unless otherwise indicated:
(A)
Lawn area (turf).
(1)
Grass areas shall be planted in species well adopted to localized growing conditions in Miami-Dade County. Grass areas may be sodded, plugged, sprigged, hydromulched, or seeded except that solid sod shall be used in swales or other areas subject to erosion. In areas where other than solid sod or grass seed is used, overseeding shall be sown for immediate effect and protection until coverage is otherwise achieved.
(2)
Exclusions from maximum permitted lawn areas:
(a)
Stabilized grassed area used for parking;
(b)
Grassed areas designated on landscape plans and actively used for sports, playgrounds or picnic areas;
(c)
Grassed areas in the right-of-way;
(d)
Stormwater retention/detention areas planted in grasses which are very drought tolerant, as referenced in the Landscape Manual, as well as tolerant to wet soils.
(3)
Maximum permitted lawn area for all residential and mixed uses in the unincorporated area is referenced in Table A.
(4)
Maximum permitted lawn area for all office, commercial, and industrial uses is as referenced in Table A. Very drought tolerant grasses and low growing native plants, including grasses and forbs, as referenced in the Landscape Manual, may be used as groundcover beyond the maximum permitted grass area specified in Table A.
(5)
In municipalities, the maximum amount of lawn area for residential and mixed uses shall be limited to a maximum of sixty (60) percent of the landscaped open space required in the individual municipal code(s). In those residential and mixed use zoning districts where landscaped open space is not specified, lawn areas shall be restricted to a maximum of fifty (50) percent of the net lot area. Lawn areas in commercial, office and industrial zones shall be limited to a maximum of twenty (20) percent of the open space required by the individual municipalities. In those commercial, office and industrial zones, where landscaped open space is not specified, lawn area shall be restricted to a maximum of twenty (20) percent of the net lot area less the area covered by buildings. Very drought tolerant grasses and low growing native plant species, including grasses and forbs, as referenced in the Landscape Manual, may be used as groundcover beyond the maximum permitted grass area.
(B)
Irrigation.
(1)
All newly-planted and relocated plant material shall be watered by temporary or permanent irrigation systems until such time as they are established and subsequently on as-needed basis to prevent stress and die-off in compliance with existing water use restrictions.
(2)
Irrigation shall be prohibited within native plant communities and natural forest communities, except for temporary systems needed to establish newly planted material. Temporary irrigation systems shall be disconnected immediately after establishment of plant communities.
(3)
Irrigation systems shall be designed, operated and maintained to:
(a)
Meet the needs of all the plants in the landscape.
(b)
Conserve water by allowing differential operation schedules based on hydrozone.
(c)
Consider soil, slope and other site characteristics in order to minimize water waste, including overspray or overflow on to impervious surfaces and other non-vegetated areas, and off-site runoff.
(d)
Minimize free flow conditions in case of damage or other mechanical failure.
(e)
Use low trajectory spray heads, and/or low volume water distributing or application devices.
(f)
Maximize uniformity, considering factors such as:
(1)
Emitters types,
(2)
Head spacing,
(3)
Sprinkler pattern, and
(4)
Water pressure at the emitter.
(g)
Use the lowest quality water feasible (graywater shall be used where approved systems are available).
(h)
Rain switches or other devices, such as soil moisture sensors, shall be used with automatic controls.
Operate only during hours and on days permitted under Chapter 32 of the Code of Miami-Dade County.
(i)
Where feasible, drip irrigation or micro-sprinklers shall be used.
(4)
During dry periods, irrigation application rates of between one (1) and one and one-half (1½) inches per week are recommended for turf areas.
(5)
If an irrigation system is not provided, a hose bib shall be provided within seventy-five (75) feet of any landscape area.
(C)
Trees.
(1)
Tree size. All trees, except street trees, shall be a minimum of ten (10) feet high and have a minimum caliper of two (2) inches at time of planting except that thirty (30) percent of the tree requirement may be met by native species with a minimum height of eight (8) feet and a minimum caliper of one and one-half (1½) inches at time of planting.
(2)
Street tree size and spacing. Street trees shall be of a species typically grown in Miami-Dade County which normally mature to a height of at least twenty (20) feet. Street trees shall have a clear trunk of four (4) feet, an overall height of twelve (12) feet and a minimum caliper of two (2) inches at time of planting, and shall be provided along all roadways at a maximum average spacing of thirty-five (35) feet on center, except as otherwise provided in this chapter. Street trees are not required when a colonnade open to the public is located within four (4) feet of the edge of the roadway. The thirty-five (35) foot average spacing requirement for multiple single family units such as zero-lot-line and townhouse shall be based on the total lineal footage of roadway for the entire project and not based on individual lot widths. Street trees shall be placed within the swale area or shall be placed on private property where demonstrated to be necessary due to right-of-way obstructions as determined by the Public Works Department or the appropriate authority within the municipality. Street trees planted along private roadways shall be placed within seven (7) feet of the edge of roadway pavement and/or where present within seven (7) feet of the sidewalk.
(3)
Power lines. Where the height and location of overhead powerlines requires the planting of low growing trees, street trees shall have a minimum height of eight (8) feet, a minimum caliper of one and one-half (1½) inches at time of planting, and shall meet the following requirements:
(a)
Single trunk trees clear of lateral branches to four (4) feet and/or multitrunk trees or tree/shrubs, as referenced in the Landscape Manual, cleared of foliage to a height of four (4) feet.
(b)
A maximum average spacing of twenty-five (25) feet on center.
(c)
Maturing to a height and spread not encroaching within five (5) feet of overhead power distribution lines.
(d)
Under high voltage (50kV and above) transmission lines installed independent of underbuilt distribution lines, tree height and spread shall not exceed the minimum approach distances specified in the current ANSI (American National Standards Institute) Z133.1 Standards, as referenced in the Landscape Manual.
(4)
Palms. Palms which meet all of the following requirements shall count as a required street tree on the basis of one (1) palm per tree.
(a)
Minimum canopy of fifteen (15) feet at maturity.
(b)
Provided at an average maximum spacing of twenty-five (25) feet on center.
(c)
Fourteen-foot minimum overall height or minimum caliper of four (4) inches at time of planting.
It is provided however that queen palms (Syagrus romanzoffiana) shall not be allowed as street trees.
(5)
Minimum number of trees. Within Unincorporated Miami-Dade County, the minimum number of required trees, in addition to street trees, is referenced in Table A.
TABLE A (See note below regarding street trees)
LAND USE OR ZONING DISTRICT NUMBER OF TREES
REQUIREDMAXIMUM LAWN AREA Per Acre of Net Lot Area Per Lot Percent of Net Lot Area Percent of
Required
Open SpaceSINGLE FAMILY RESIDENTIAL AND DUPLEX
RU-1 - 3 50% - RU-1M(a) - 3 35% - RU-1M(b) - 3 35% - RU-1Z - 3 35% - RU-2 - 3 50% - TOWN HOUSE
RU-TH 28 - - 60% ESTATE USE
EU-M 9 - 50% - EU-S 9 - 50% - EU-1 9 - 60% - EU-2 9 - 60% - EU-1C 9 - 60% - MULTI-FAMILY RESIDENTIAL
RU-3 28 - 60% - RU-3B 28 - 60% - RU-3M 28 - - 60% RU-4L 28 - - 60% RU-4M 28 - - 40% RU-4 28 - - 40% RU-4A 28 - - 40% OFFICE
RU-5 28 - - 30% RU-5A 28 - - 30% OPD 28 - - 30% COMMERCIAL
BU-1 22 - - 20% BU-1A 22 - - 20% BU-2 22 - - 20% BU-3 22 - - 20% INDUSTRIAL
IU-1 15 - - 20% IU-2 15 - - 20% IU-3 15 - - 20% IU-C 22 - - 20% MISCELLANEOUS ZONING DISTRICTS AND LAND USES
Planned Developments 28 - - 40% Planned Area Developments 28 - - 40% Private Educational Facilities 28 - - 40% TND 28 - - 40% GU Interim* 9 - 60% - AU Agriculture (Residential Use) 9 - 60% - All Other Zoning Districts 28 - 60% - * Use dependent on character of neighborhood, otherwise EU-2 standards apply.
** Unusual uses must comply with the requirements of underlying zoning district.
In addition to the number of trees indicated in Table A, additional trees (street trees) may be required as provided in Section 18A-6(C).
(6)
Grassed areas that are to be used for organized sports such as football and soccer or other similar sports or playgrounds, that are clearly identified on a landscape plan shall not be counted toward calculating tree requirements.
(7)
Trees shall be planted to provide shade to residential structures of a height of thirty-five (35) feet or less. At least two (2) required lot trees shall be positioned in the energy conservation zone as defined herein. All exterior air conditioning units, except for air conditioning units placed on the roof, shall be shaded by trees and/or shrubs as referenced in the Landscape Manual.
(8)
Palms of a ten-foot minimum overall height or minimum caliper of three (3) inches at time of planting shall count as a required tree on the basis of two (2) palms-per tree, except as provided herein for palms used as of street trees. No more than thirty (30) percent of the minimum tree requirements may be met by palms.
(9)
Existing trees required by law to be preserved on site and that meet the requirements of Section 18A-6(C), may be counted toward fulfilling the minimum tree requirements.
(10)
Prohibited and controlled tree species shall not be counted toward fulfilling minimum tree requirements. Prohibited trees shall be removed from the site.
(11)
Of the required trees at least:
(a)
Thirty (30) percent shall be native species; and
(b)
Fifty (50) percent shall be low maintenance and drought tolerant; and
(c)
No more than thirty (30) percent shall be palms.
(12)
Eighty (80) percent of the trees shall be listed in the Miami-Dade Landscape Manual, the Miami-Dade Street Tree Master Plan and/or the University of Florida's Low-Maintenance Landscape Plants for South Florida list.
(13)
In order to prevent adverse environmental impacts to existing native plant communities, cabbage palms (Sabal palmetto) that are harvested from the wild shall not be used to satisfy minimum landscaping requirements. Only existing cabbage palms, which are rescued from government approved donor sites, transplanted within the site, or commercially grown from seed shall be counted towards the minimum tree and native plant requirements.
(14)
When trees are planted within the right-of-way, the owners of land adjacent to the areas where street trees are planted must maintain those areas including the trees, plants and sod, using pruning methods specified in this Code. A covenant executed by those owners is required, or a special taxing district must be created to maintain these areas. Where the State, County or municipality determines that the planting of trees and other landscape material is not appropriate in the public right-of-way, they may require that said trees and landscape material be placed on private property.
(15)
Consideration shall be given to the selection of trees, plants and planting site to avoid serious problems such as clogged sewers, cracked sidewalks, and power service interruptions.
(16)
Municipalities shall meet all the above requirements in the corresponding zoning districts or land use categories of the particular municipality.
(D)
Shrubs.
(1)
All shrubs shall be a minimum of eighteen (18) inches in height when measured immediately after planting. Shrubs shall be provided at ratio of ten (10) per required tree. Of the provided shrubs at least:
(a)
Thirty (30) percent shall be native species; and
(b)
Fifty (50) percent shall be low maintenance and drought tolerant; and
(c)
Eighty (80) percent shall be listed in the Miami-Dade Landscape Manual, the Miami-Dade Street Tree Master Plan and/or the University of Florida's Low-Maintenance Landscape Plants for South Florida list.
(2)
When used as a visual screen, buffer, or hedge, shrubs shall be planted at a maximum average spacing of thirty (30) inches on center or if planted at a minimum height of thirty-six (36) inches, shall have a maximum average spacing of forty-eight (48) inches on center and shall be maintained so as to form a continuous, unbroken and solid visual screen within one (1) year after time of planting. Shrubs used as a buffer, visual screen, or hedge need not be of the same species.
(E)
Vines. Vines shall be a minimum of twelve (12) inches in length immediately after planting and may be used in conjunction with fences, screens, or walls to meet physical barrier requirements as specified. Planting of perimeter walls with vines is recommended as a deterrent to painting of graffiti.
(F)
Ground covers. Ground cover plants used in lieu of grass, in whole or in part, shall be planted in such a manner as to present a finished appearance and reasonably complete coverage within one (1) year after planting.
(G)
Mulch.
(1)
Mulches shall be applied and maintained in accordance with the most recent edition of the Florida Yards and Neighborhoods Handbook titled "A Guide to Florida Friendly Landscaping" by the University of Florida, Institute of Food and Agricultural Sciences (UF/IFAS) and available online at http://www.floridayards.org/landscape/FYN-Handbook.pdf.
(2)
Cypress mulch shall not be used because its harvest degrades cypress wetlands.
(H)
Buffers between dissimilar land uses. Where dissimilar land uses exist on adjacent properties, and where such areas will not be entirely visually screened by an intervening building or structure from abutting property, that portion of such area not so screened shall be provided with a buffer consisting of a six (6) foot wall or fence with a life expectancy of at least ten (10) years, or shrubs which normally grow to a minimum height of six (6) feet. Where chain link fencing is used, shrubs shall also be required. Shrubs used as a buffer shall be a minimum of thirty (30) inches in height at time of planting, and shall be planted at a maximum average spacing of thirty-six (36) inches on center, or a minimum of thirty-six (36) inches in height at time of planting and planted at a maximum average spacing of forty-eight (48) inches on center. Said buffer shall form a continuous screen between the dissimilar land uses within one (1) year after planting. Buffers screening dissimilar uses shall include trees planted at a maximum average spacing of thirty-five (35) feet on center within a minimum five (5) foot landscaped strip.
(I)
Parking lot buffers. All parking lots adjacent to a right-of-way or private street shall be screened by a continuous planting and/or three (3) foot high wall with a seven (7) foot landscaped strip incorporating said planting and/or wall on private property. Planting material at time of planting shall be either a minimum height of eighteen (18) inches with a maximum average spacing of thirty (30) inches on center, or a minimum height of thirty-six (36) inches with a maximum average spacing of forty-eight (48) inches on center.
(J)
Landscaped areas in parking lots. Ten (10) square feet of landscaped area per parking space shall be provided within a parking lot. In order to maximize the distribution of shade, trees shall be planted throughout the interior of the parking lot at a minimum density of one (1) tree per eighty (80) square feet of landscaped area, exclusive of parking lot buffers. Planting areas for each tree shall have a minimum width of five (5) feet, exclusive of the curb dimension, and shall be planted or covered with other landscape materials. This requirement is in addition to any applicable required open space as provided in Chapter 33 of the Code of Miami-Dade County or applicable municipal code.
(K)
Plant quality.
(1)
Plants installed pursuant to this Code shall conform to, or exceed, the minimum standards for Florida Number One as provided in the most current edition of "Grades and Standards for Nursery Plants, Part I and II," prepared by the State of Florida Department of Agriculture and Consumer Services.
(2)
Trees installed pursuant to this Code shall have one (1) primary vertical trunk and secondary branches free of included bark up to a height of six (6) feet above natural grade.
(L)
Stormwater retention/detention areas.
(1)
Stormwater retention/detention areas shall be designed to maximize the perimeter dimension, where feasible.
(2)
Stormwater retention/detention areas shall be planted throughout with native herbaceous facultative plants, with the following exceptions:
(a)
In areas that are designated and actively used for play and/or picnic areas, overflow parking, or sports shall be planted with grasses which are very drought tolerant, as referenced in the Landscape Manual, as well as tolerant to wet soils.
(b)
In areas where the minimum required stormwater retention capacity would be adversely affected.
(3)
The minimum required number of native herbaceous facultative plants shall be one (1) plant per square foot of retention/ detention area, including the slope. Minimum required herbaceous plant container size shall be one and one-half (1½) inches, commonly, referred to as a liner. Sprigging, seeding, plugging, hydro-mulching or sodding with native herbaceous facultative plants grown from local seed sources may be used in lieu of liners. Herbaceous plants shall be planted in such a manner as to present a finished appearance and reasonably complete coverage within one (1) year after planting.
(4)
Native facultative trees or shrubs may be used in lieu of native herbaceous facultative plants, provided that the minimum required stormwater retention capacity is not adversely affected.
(Ord. No. 95-222, § 2, 12-5-95; Ord. No. 97-90, § 1, 6-17-97; Ord. No. 98-13, § 1, 1-13-98; Ord. No. 09-35, § 4, 5-5-09)